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Proliferation Security Initiative (PSI)

The Global Nuclear Security Grand Challenge

Technology for Global Security is announcing the Global Nuclear Security Grand Challenge to answer the question: “What is the best system design for countries, companies, and other organizations to confidentially and securely verify in real time that 100 percent of their nuclear weapons and weapons-usable fissile material remains in their control and to aid in the recovery of any loss if it occurs?” A great deal of progress has been made since the launch of the Nuclear Security Summits initiated by President Obama in 2010 . The equivalent of 130 nuclear weapons' worth of highly enriched...

States Meet to Enhance WMD Initiative

More than 70 countries convened to update informal, joint interdiction actions. 

March 2016

By Kelsey Davenport

Members of seven countries participate in an exercise known as Adriatic Shield as part of the Proliferation Security Initiative in the waters near the Croatian port city of Rijeka on May 13, 2008. (Photo credit: Stringer/AFP/Getty Images)Representatives from 71 countries met in Washington in January to discuss plans for strengthening an initiative designed to disrupt shipments of materials and technologies used for developing nonconventional weapons.

At a Jan. 28 press briefing, Thomas Countryman, U.S. assistant secretary of state for international security and nonproliferation, said that participants at the previous day’s midlevel political meeting of the Proliferation Security Initiative (PSI) discussed topics such as trends in proliferation, tactics that networks use to ship sensitive materials and technologies, and options to control proliferation financing. Countryman also said that countries shared expertise and resources that should contribute to building countries’ ability to carry out interdictions.

Launched by the George W. Bush administration in May 2003, the PSI is an informal, voluntary arrangement without a permanent institutional structure. It seeks to enhance participants’ capacity to interdict illegal trafficking of weapons of mass destruction (WMD), related materials and technologies, and WMD delivery systems through international cooperation.

The January meeting marked the midpoint between the last high-level political meeting, in Poland in 2013, and the next, scheduled to take place in France in 2018. The United States committed to hosting the midlevel meeting at the 2013 meeting in Poland, which also celebrated the initiative’s 10th anniversary.

The initiative does not create new international law. Instead, it relies on existing legal instruments and national authorities to allow states to conduct interdictions and share information about illicit trafficking of dual-use technologies.

Currently, 105 countries participate in the initiative. To join, a country must endorse the statement of principles, which aims to “establish a more coordinated and effective basis through which to impede and stop shipments of WMD, delivery systems, and related materials flowing to and from states and non-state actors of proliferation concern.”

The PSI does not typically publish cases of successful disruption of WMD-related trafficking. However, in May 2008, the U.S. State Department released a description of five PSI efforts. These interdictions included stopping shipments of materials for Iran’s nuclear program and of ballistic missile components heading to Syria. (See ACT, July/August 2008.)

The chairman’s summary of the Jan. 27 meeting said that, over the next two years, participating states will work harder to “improve their individual and collective interdiction capabilities through regional and global activities, exercises, workshops, actual interdictions as they occur, and continuous reassessments of the proliferation environment.”

A European official who is involved with the PSI said in a Feb. 4 interview that greater emphasis on regional exercises is important because proliferation threats can vary from region to region, as do “needs to strengthen capacities and strategies to combat proliferation networks.”

Speaking at the Jan. 28 briefing, Wendin Smith, U.S. deputy assistant secretary of defense for countering weapons of mass destruction, emphasized that the initiative has created a “flexible network” that “continues to evolve” to meet proliferation threats.

But the European official said the PSI does not have a strategy to expand its membership and that “not enough is being done to recruit key countries to join the initiative.”

The official said the PSI would benefit from Chinese, Indian, and Pakistani participation. Those countries, which possess WMD-related technologies and materials, could take steps to strengthen their national capacities to impede shipments of dual-use materials and technologies, he said.

At the press briefing, Countryman said the United States would welcome new participants such as China, India, and Indonesia to endorse the initiative’s principles and participate in exercises and workshops.

Countryman said participation of these countries in the initiative would “enhance the efficiency” of UN Security Council sanctions.

Most planning for the initiative takes place during meetings of the PSI Operational Experts Group, which comprises 21 states, primarily from Europe and North America. That group is to meet in the United Kingdom in April.

Posted: March 2, 2016

How Should Washington Respond to Iran’s Ballistic Missile Tests?

Iran’s recent ballistic missile tests, while extremely unhelpful, should not come as a surprise. And although the missile tests violate UN Security Council Resolution 1929, they are not a violation of the soon-to-be-implemented nuclear deal between six world powers and Iran. There should be consequences for violations of Security Council resolutions. However, U.S. policymakers should put the risks posed by the missile tests in perspective and pursue effective actions that address the violation, but do not undermine progress toward reducing Iran’s nuclear potential. Despite the passage of UN...

Strengthening the Proliferation Security Initiative Can Bolster the Iran Deal

In April 2007, a shipment of sodium perchlorate bound for Iran was detoured to an Asian port and then returned to the country of origin. Six months earlier, in November 2006, a shipment of chromium-nickel steel plates were interdicted en route to Iran and returned to the supplier country. Both materials can be used for the development of ballistic missiles and were shipped to Iran in contravention of UN Security Council resolutions . These two cases epitomize the achievements of the Proliferation Security Initiative (PSI) , which has been instrumental in identifying and interrupting numerous...

Congress Finally Passes Legislation to Prevent and Counter Nuclear Terrorism

Today, as part of the USA Freedom Act, the Senate passed language to implement key requirements of two important, and long overdue agreements that strengthen global efforts to prevent and counter nuclear terrorism, paving the way for their ratification. The two agreements —the 2005 amendment to the Convention on the Physical Protection of Nuclear Material (CPPNM) and the 2005 International Convention on the Suppression of Acts of Nuclear Terrorism (ICSANT) – require state parties to better protect nuclear materials and to punish acts of nuclear terrorism. While the United States already has...

U.S., Allies to Strengthen WMD Initiative

The United States and other participants in the Proliferation Security Initiative (PSI) will seek new legal authorities to conduct interdictions of shipments of goods...

Ian Williams

The United States and other participants in the Proliferation Security Initiative (PSI) will seek new legal authorities to conduct interdictions of shipments of goods related to weapons of mass destruction (WMD) and will begin conducting more-regular interdiction exercises, the U.S. State Department announced in a May 28 press release.

The announcement came after delegates from 72 states met for a high-level political meeting in Warsaw May 27-28 to commemorate the initiative’s 10th anniversary and discuss its future. The PSI seeks to increase participants’ capacity to interdict illegal trafficking of nonconventional weapons, their delivery systems, and related materials through international cooperation. The initiative, which was launched by President George W. Bush in May 2003, is an informal, voluntary arrangement without a permanent institutional structure. To date, 102 countries have endorsed the PSI.

At the Warsaw meeting, the United States pledged to finalize accession to the 2005 protocol to the Convention for the Suppression of Unlawful Acts Against the Safety of Maritime Navigation and the 2010 Convention on the Suppression of Unlawful Acts Relating to International Civil Aviation. The conventions criminalize the transportation by ship or aircraft of materials related to nuclear, biological, and chemical weapons.

The PSI itself does not create new law. Instead, it relies on existing legal instruments to give states the authority to conduct interdictions. The United States signed the maritime convention in 2006 and the aviation convention in 2010, but the Senate has yet to approve them.

The event in Warsaw was the first high-level meeting in five years. Most planning for the initiative takes place during meetings of the PSI Operational Experts Group, which occur more frequently. The experts group comprises 21 states, primarily from Europe and North America.

In its 2010 National Security Strategy document, the Obama administration pledged to turn the initiative into a “durable international effort.” A recent report from the Stockholm International Peace Research Institute said the initiative could benefit from reforms such as increasing the experts group’s geographic diversity. In a June 20 e-mail to Arms Control Today, a U.S. State Department official said there had been no discussion of reforming the experts group at the Warsaw meeting.

The official said that the United States is aiming to promote PSI participation in Southeast Asia, Africa, and the Western Hemisphere.

Posted: July 2, 2013

The Proliferation Security Initiative (PSI) At a Glance

October 2016

Contact: Kelsey Davenport, Director for Nonproliferation Policy, (202) 463-8270 x102

Updated: October 2016

President George W. Bush announced May 31, 2003 that the United States would lead a new effort, the Proliferation Security Initiative (PSI), to interdict shipments of weapons of mass destruction (WMD) and related goods to terrorists and countries of proliferation concern. The initiative's aim would be "to keep the world's most destructive weapons away from our shores and out of the hands of our common enemies," Bush declared.

Participants: Ten countries originally joined with the United States to shape and promote the initiative. These countries are Australia, France, Germany, Italy, Japan, the Netherlands, Poland, Portugal, Spain, and the United Kingdom. In total, 105 countries have publicly committed to the initiative. Membership in PSI only requires a state to endorse the PSI Statement of Interdiction Principles, a non-binding document that lays out the framework for PSI activities. PSI participants have downplayed the concept of membership in the initiative, explaining in a press statement that PSI is "an activity not an organization."[1] U.S. officials have courted China to join the regime, but so far it has kept its distance, citing concerns about the legality of interdictions.

Mission: The initiative aims to stop shipments of biological, chemical, and nuclear weapons, as well as missiles and goods that could be used to deliver or produce such weapons, to terrorists and countries suspected of trying to acquire WMD. Initiative participants intend to carry out cargo interdictions at sea, in the air, or on land. For some countries this is not a new practice but an enshrinement and expansion of current operations. The United States and other countries have long records of intercepting illegal trade and smuggling activities, including illicit weapons transactions.

Still, the initiative is designed to make it more costly and risky for proliferators to acquire the weapons or materials they seek. By doing so, members hope that other countries will be dissuaded from pursuing weapons in the first place or experience significant delays in their acquisition efforts.

PSI is limited to stopping shipments of WMD and dual-use goods-items that have both civilian, peaceful purposes and that can be used to make weapons-to those countries and nonstate actors viewed as threats by PSI participants. Then-Undersecretary of State for Arms Control and International Security John Bolton indicated in November 2003 that participants will not be targeting the trade of countries perceived as U.S. allies or friends, such as India, Israel, and Pakistan-all three of which possess WMD arsenals, including nuclear weapons.

Principles: The 11 original PSI participants released a set of principles September 4, 2003.[2] The principles call on PSI participants, as well as other countries, to not engage in WMD-related trade with countries of proliferation concern and to permit their own vessels and aircraft to be searched if suspected of transporting such goods. The principles further urge that information on suspicious activities be shared quickly to enable possible interdictions and that all vessels "reasonably suspected" of carrying dangerous cargo be inspected when passing through national airports, ports, and other transshipment points.

Legal Authority: The initiative does not create new law, but rather relies on existing international law to conduct interdictions in international waters or airspace. For example, a ship can be stopped in international waters if it is not flying a national flag or properly registered. It cannot be stopped simply because it is suspected of transporting WMD or related goods. PSI is primarily intended to encourage participating countries to take greater advantage of their own existing national laws to intercept threatening trade passing through their territories, where they have jurisdiction to act. In situations where the legal authority to act may be ambiguous, Bolton said participants might go to the UN Security Council for authorization.[3]

Although the initiative does not create new law, PSI participants are encouraged to develop their national laws and help promote international treaties that criminalize WMD related trafficking.  PSI member states also seek to expand their legal authority to interdict shipments by signing bilateral boarding agreements with select countries to secure expedited processes or pre-approval for stopping and searching their ships at sea. The United States has concluded such agreements with Antigua and Barbuda, Bahamas, Belize, Croatia, Cyprus, Liberia, Malta, the Marshall Islands, Mongolia, Panama and St. Vicent and the Grenadines. Liberia and Panama possess the largest fleets of registered ocean-going vessels in the world.

Structure: PSI is an informal arrangement among countries. To date, there is no list of criteria by which interdictions are to be made (except that the cargo is destined for a recipient that might use it to harm the United States or other countries). There is also no secretariat or formal organization that serves as a coordinating body. Instead, participants aim to readily share information among one another as appropriate and to act when necessary to help seize or thwart dangerous trade. One forum for coordination among PSI members is Operational Experts Group (OEG). The OEG consists of delegations from the most active PSI members, which meet periodically to plan exercises, discuss recent interdictions, and share relevant information. There are currently 21 states that participate in the OEG.

Activities and Interdictions: PSI participants have conducted nearly 50 interdiction exercises since the initiative's inception. The exercises, including mock ship boardings, are intended to increase the participants' capabilities to cooperate with one another. They are also intended to put a public face on the initiative and act as a deterrent to potential proliferators.

U.S. officials claim that there have been successful interdictions since the initiative's launch. In a June 2006 speech, then-Undersecretary of State Robert Joseph claimed that between April 2005 and April 2006 the United States had cooperated with other PSI participants on “roughly two dozen” occasions to prevent transfers of concern. Ulrik Federspiel, Denmark’s ambassador to the United States, asserted at a May 2005 event that “the shipment of missiles has fallen significantly in the lifetime of PSI.”

A recent example of a PSI success was the June 2011 interdiction of the M/V Light, a Belizean flagged freighter suspected of carrying ballistic missile technology from North Korea to Myanmar. U.S. naval forces intercepted the vessel, and forced it to return to North Korea. Although the M/V Light was turned back before it was inspected, the United States would have had the legal authority to do so through its ship-boarding agreement with Belize, a PSI member state.

Status: On May 28, 2013, representatives from seventy-two PSI member states held a High Level Political Meeting in Warsaw on the 10th anniversary of the PSI’s formation. Attending states affirmed four joint statements pledging to conduct “more regular and robust” PSI exercises; promote international treaties criminalizing WMD-related trafficking; share expertise and resources to enhance interdiction capabilities; and to expand “the influence of the PSI globally through outreach to new states and the public.”[4] This was followed by a mid-level meeting in Washington, DC in January 2016 that included representatives from 71 countries. Thomas Countryman, U.S. assistant secretary of state for international security and nonproliferation, said that participants discussed topics such as trends in proliferation, tactics that networks use to ship sensitive materials and technologies, and options to control proliferation financing. Countryman also said that countries shared expertise and resources that should contribute to building countries’ ability to carry out interdictions.

The United States pledged at the 2013 Warsaw meeting to accede to the 2005 Protocol to the Convention for the Suppression of Unlawful Acts Against the Safety of Maritime Navigation. The United States deposited its ratification in August 2015. 


updated by Ian Williams




1. Proliferation Security Initiative: Chairman's Conclusions at the Fourth Meeting, October 10, 2003. London, United Kingdom. http://www.state.gov/t/isn/115305.htm

2. Proliferation Security Initiative: Statement of Interdiction Principles, September 4, 2003. Paris, France. http://www.state.gov/t/isn/c27726.htm.

3. John Bolton, interviewed by Wade Boese, November 4, 2003. Arms Control Today, December 2012.

In the interview Bolton stated, "And the 11 PSI countries also talked about circumstances where one could envision a Security Council resolution that might give authority in certain circumstances." http://www.armscontrol.org/act/2003_12/PSI

4. Proliferation Security Initiative: 10th Anniversary High-Level Political Meeting Outcomes. May 28, 2013. Office of the Spokesperson: Bureau of International Security and Nonproliferation, U.S. Department of State http://www.state.gov/r/pa/prs/ps/2013/05/120010.htm

5. Ibid.

Nuclear/Ballistic Missile Nonproliferation

Posted: June 10, 2013

GAO Report Calls for Revamped PSI

Peter Crail

Since 2003, U.S. officials have credited the Proliferation Security Initiative (PSI) with a number of successes in preventing the transfer of unconventional weapons materials to states and nonstate actors. According to a Nov. 10 Government Accountability Office (GAO) report, however, key U.S. agencies have not established performance indicators to assess the PSI's effectiveness nor have they outlined clear policies, procedures, or funding requirements for activities associated with the initiative, as called for by Congress. The report appears to highlight a dispute between U.S. agencies and Congress regarding how Washington should carry out this initiative and what needs to be done to strengthen it.

The PSI was launched in May 2003 as part of an increased effort by the Bush administration to address the risks of unconventional weapons proliferation. According to the statement of interdiction principles concluded by the 11 founding states at that time, the effort is intended to "establish a more coordinated and effective basis through which to impede and stop shipments of [unconventional weapons], delivery systems, and related materials." Since its founding, the initiative has grown to 93 participants that have endorsed this statement of principles.

Defining PSI Activities

The architects of the initiative, including then-Undersecretary of State for Arms Control and International Security John Bolton, described the PSI as an activity rather than an organization. (See ACT, December 2003.) Bolton told Arms Control Today in December 2003 that the PSI was primarily intended to enhance existing multilateral efforts already being carried out by U.S. agencies.

In legislation adopted in August 2007, Congress recommended that the administration provide more specific guidance to U.S. agencies on how to implement the initiative. The Implementing Recommendations of the 9/11 Commission Act of 2007 suggested that the president issue a directive to "establish clear PSI authorities, responsibilities, and structures." (See ACT, September 2007.) The 2007 legislation also required that the Departments of Defense and State establish a comprehensive joint budget each year for PSI-related activities. These congressional recommendations were originally contained in a classified 2006 GAO report assessing PSI implementation.

In response to the GAO recommendations, the administration has asserted that PSI interdiction activities are already guided by a 2002 presidential national security directive governing WMD-related interdictions and that, in regard to other aspects of the PSI, such a directive is unnecessary. In an Oct. 17 response to the draft GAO report, the State Department indicated that National Security Council (NSC) staff chair an interagency policy coordination committee on the PSI that implements "clearly defined strategy documents" that describe agency roles and responsibilities.

The State Department also rejected the need for a joint PSI budget, stating in its Oct. 17 letter that, rather than a single distinct program, the PSI is "a set of activities interwoven into the [U.S. government's] established diplomatic, military, and law enforcement relations with other countries." The State Department said that each agency should establish their own budget items for the PSI.

In addition to the Defense and State Departments, agencies involved in PSI-related activities include the Coast Guard, Customs and Border Protection, and the Federal Bureau of Investigation. The GAO indicated that none of these agencies include PSI funding in their annual budgets.

The GAO also criticized U.S. agencies for failing to establish performance indicators to assess the effectiveness of PSI activities. The report argued that, without such indicators, "it will be difficult for policymakers to objectively assess the relevant U.S. agencies' contributions to PSI activities over time."

Indeed, many of the successes that the administration has attributed to the PSI have been the result of activities that U.S. agencies had carried out prior to its establishment. A number of these interdictions were described during a June 6 briefing to nongovernmental organizations on the initiative. (See ACT, July/August 2008.) The interdictions ranged from halting a shipment of missile test equipment to Syria during transshipment to denying an export license of materials that may have been intended for Iran's nuclear program.

U.S. officials pointed out during the briefing that these interdictions were carried out in the furtherance of international law, such as UN Security Council resolutions, or national legal authorities, such as export controls. It is uncertain, therefore, what contribution the PSI had in carrying out these interdictions given their reliance on existing legal authorities and agency activities.

It is also unclear if PSI activities are limited to formal PSI participants. The Wall Street Journal reported Nov. 1 that India denied a request in August by a North Korean plane for passage through Indian airspace en route to Iran at the urging of the United States as part of a PSI effort. India is not a member in the PSI, but it has participated as an observer in PSI meetings and exercises.

In spite of questions about the administration's approach to the PSI, changes do not appear likely under the next administration. Although President-elect Barack Obama called for strengthening the PSI "through appropriate measures" in nonproliferation legislation he proposed in 2007, a congressional source told Arms Control Today Nov. 21 that the initiative "will be a very low priority for the incoming administration." The source doubted whether there would be any major changes and suspected that senior-level Obama administration policymakers believe that its value and successes were exaggerated and "provided an excuse for the Bush administration to ignore other, more critical aspects of its nonproliferation record."

Expanding PSI Cooperation

Among the initiative's 93 participants, 20 states constitute the initiative's Operational Experts Group, which meets on a regular basis to coordinate PSI-related efforts. Experts group members include the United States and several of its European allies, as well as Australia, Japan, and Russia.

One of the two key recommendations of the GAO report was the need to establish greater coordination with PSI participants that are not part of the leading experts group. In particular, the GAO noted that more than 70 participants not part of the experts group have little involvement in efforts to increase cooperation and coordination and that, of the 36 interdiction exercises held between September 2003 and September 2008, only six involved non-experts group states.

Many of these non-experts group states are situated in regions or locations of particular concern for illicit trafficking in unconventional weapons materials, including the Caucasus, Central Asia, the Persian Gulf, and Southeast Asia.

The report noted that the Defense and State Departments recognized the need to expand cooperation with these states. The State Department highlighted its outreach efforts and indicated that it intended to hold a PSI meeting for the Western Hemisphere in May 2009 involving PSI members from Latin America.


Posted: December 4, 2008

Interdiction Initiative Successes Assessed

Wade Boese

Commandos rappelling down ropes from a helicopter to a ship deck or navy forces boarding a vessel at sea are images often associated with a Bush administration initiative to intercept unconventional weapons or related cargo in transit. Actual interdictions tend to be less dramatic. Recently disclosed incidents involved export control and customs officials denying export licenses and transfers, as well as air traffic authorities refusing overflight rights to planes allegedly transporting suspicious goods.

U.S. officials detailed those interdictions as part of a Washington conference marking the five-year anniversary of the May 31, 2003, unveiling of the Proliferation Security Initiative (PSI). (See ACT, July/August 2003 .) Initially comprised of 11 countries, the voluntary initiative has grown to more than 90 participants who have committed to intercept items of proliferation concern at sea, on land, and in the air before they reach their final destination.

Representatives of more than 80 countries attended the May 28-29 conference, the second day of which focused on expanding participation in the initiative. Officials from 21 nonparticipants, including China, India, and Pakistan, were present at the meeting. Those three countries, as well as others, have questioned the legality of interdictions and the initiative itself despite assurances from participants that all activities are consistent with international law. 

Assessing the PSI’s results has been difficult. Governments have been reticent to discuss specific interdictions publicly, claiming that to do so might imperil future operations by exposing intelligence sources and methods relied on to get useful information. In a June 6 briefing to nongovernmental groups, U.S. officials said even they are unaware of all PSI activities because participants keep some operations secret from each other.

Current and former U.S. officials periodically have issued vague claims of success. For instance, one U.S. official at the June briefing said there have been “several instances” in which suspect planes have been prevented from completing their flights due to governments refusing to let the aircraft fly over their territories.

In a May 28 op-ed in The Washington Times, Robert Joseph, a PSI architect and former undersecretary of state for arms control and international security, and Brendan Melley, a former National Security Council official from 2001 to 2005, reported that “dozens of interdictions have taken place slowing nuclear and missile programs in Asia and the Middle East.”

The two former Bush administration officials implied a specific PSI triumph was the October 2003 confiscation of centrifuge technology bound for Libya aboard a ship, the BBC China. But foreign government officials familiar with that interdiction and John Wolf, the assistant secretary of state for nonproliferation at the time, have disputed that it was a PSI operation, asserting that the cargo seizure stemmed from activities preceding the initiative. (See ACT, July/August 2005. )

The discrepancy stems in part from the fact that the PSI, which participants describe as “an activity, not an organization,” is more of a call to action than a program with dedicated budgets, staff, and capabilities. A second U.S. government official at the June briefing noted, “[T]here are not any capabilities that are exclusively PSI.”

Instead, the initiative is based on encouraging countries to increase their cooperation and information sharing to counter proliferation. They also are supposed to make better use of and build on their pre-existing national capabilities and legal authorities to intercept suspicious or deadly cargo. As these capabilities expand, U.S. officials contend the channels through which proliferators can operate freely will shrink and their costs of doing business will increase.

Those of the opinion that the BBC China incident constitutes a PSI success seemingly classify all activities by participants since the initiative’s inception to halt questionable transactions as falling under the PSI. Indeed, a third U.S. official at the June briefing defined a PSI success as when “you stop anything from going to a proliferation destination.”

On the Washington conference’s second day, the U.S. government described five of those instances. Three of the cases involved missile- and nuclear-related cargo destined for Iran, while Syria was the intended recipient of missile-related goods in the other two examples. (See box.)

A trio of the interdictions entailed states stopping shipments that allegedly violated separate UN Security Council resolutions restricting certain missile and nuclear transfers to Iran or from North Korea. Another of the reported successes resulted from a government refusing an export license for a transfer because it contravened that state’s export controls. Given that those four transactions were inconsistent with national or international law, it is unknowable whether states would have worked together to halt them without the PSI.

In two of the cases, the exports in question never left the potential supplier’s territory, while the intercepted transfers in the other three incidents, including some U.S.-manufactured equipment, were returned to the state of origin. The third U.S. official at the June briefing pointed out that most of the goods in proliferation transactions are legal but recipients of concern pursue the items for arms programs through illegal methods, such as using front companies or fake manifests.

The first U.S. official added that “the end user is paramount” in identifying unacceptable trade and triggering action. Washington has been clear that it sees the PSI as a tool to impede trade involving Iran, North Korea, and Syria, but not U.S. allies and friends such as India and Pakistan, which developed covert nuclear procurement networks. (See ACT, December 2003 .) 

Despite the allure of interdictions, U.S. officials at the June briefing downplayed counting such operations as an accurate yardstick of the PSI’s value. They said the initiative’s worth is measured in what they claim are the growing individual and collective capabilities of participants to curb proliferation.

Examples frequently highlighted by U.S. officials are the eight bilateral shipboarding agreements that the United States has negotiated with other governments, Mongolia being the most recent in October 2007. The arrangements establish expedited procedures to allow searches of suspicious ships under those states’ legal authorities. U.S. officials say that 35 interdiction exercises, which have involved more than 70 countries, also demonstrate increasing capabilities.

Exercises and other PSI operational aspects are determined by the Operational Experts Group. The group is comprised of 20 states, including the United States and the other 10 original participants (Australia, France, Germany, Italy, Japan, the Netherlands, Poland, Portugal, Spain, and the United Kingdom). It generally meets three to four times annually, and its next meeting will occur Sept. 24-26 in Paris.


Recently Claimed Proliferation Security Initiative Successes

As part of a May 29 briefing for foreign government officials attending a Proliferation Security Initiative conference in Washington, the U.S. government provided five examples of purported PSI interdictions. The Department of State later distributed that briefing paper June 17 to some nongovernmental entities, including Arms Control Today. Below are brief descriptions of the five incidents.

February 2005: The United States tipped off a European government that one of its national entities was preparing to ship coolers to Iran that could be used in that country’s heavy-water reactor program. Heavy-water reactors have served as a key source of plutonium in the nuclear bomb efforts of India, Israel, and Pakistan. The European government investigated the claim and denied an export license for the coolers in accordance with a national law controlling such exports to Iran.

November 2006: The transfer of chromium-nickel steel plates to Iran by an Asian company was stopped in a third country. The steel plates, which reportedly could be used in missile components, were returned to the original supplier country. The interdicting state acted in accordance with UN Security Resolution 1696, which calls on states to prevent transfers of items to Iran that could contribute to its ballistic missile programs.

February 2007: Unspecified sources alerted port authorities in an unidentified state to a shipment destined for Syria of U.S.-origin equipment that could be employed for testing ballistic missile components. Those authorities conducted an inspection, seized the equipment, and returned it to the United States. A foreign firm had served as the intermediary for the attempted Syrian purchase of eight vibration test systems and eight humidity chambers.

April 2007: A shipment of sodium perchlorate to Iran from an unspecified source was detoured to an Asian port, whose government then sent the shipment back to the country of origin. The sodium perchlorate, which can be used in making solid rocket propellant for ballistic missiles, was intended for an Iranian entity barred from receiving certain missile technologies by UN Security Council Resolution 1737.

June 2007: An unidentified country denied overflight rights to a Syrian plane scheduled to make a round-trip flight to North Korea. The denial stemmed from the United States sharing suspicions that the intended cargo was related to ballistic missiles. UN Security Council Resolution 1718 obligates countries to cooperate in preventing transfers of ballistic missiles and related technologies from North Korea. The Syrian flight did not occur.



Posted: August 7, 2008

The Proliferation Security Initiative: A Glass Half-Full

Mark J. Valencia

As we approach the fourth anniversary of President George W. Bush’s May 31, 2003, launch of the Proliferation Security Initiative (PSI), it is appropriate and fair to compare rhetoric with reality, assess the effort’s effectiveness, and attempt to divine the way forward. The PSI was announced with considerable fanfare in Krakow, Poland, as an activity designed to prevent the spread of weapons of mass destruction (WMD), their delivery systems, and related materials from entering or leaving states “of proliferation concern.”

The focus was to be on interdiction because of the fear of rapid growth in states and groups pursuing WMD programs, worries of an expanding nexus between weapons of mass destruction and terrorism, and gaps in the existing nonproliferation architecture.[1] It was thought that interdiction could fill the gaps by ensuring commitments are kept and by stopping proliferation-related exports from states whose activities fall outside existing source-based nonproliferation regimes. At the least, it was assumed that it would deter suppliers and customers and make proliferation more costly and difficult. Although interdiction was not novel to the PSI, the focus on this tool elevated consideration of its use at borders, in ports, in the air, and at sea. 

The Bush administration clearly had high hopes and expectations for the PSI. On the first anniversary of its initiation, John Bolton, then undersecretary of state for arms control and international security, proclaimed that the PSI would evolve to the point where it “will have shut down the ability of persons, companies, or other entities to engage in this deadly trade.”[2] He claimed that the PSI was “succeeding because it is based on practical actions that make maximum use of each country’s strengths to counter proliferation. The partnerships being forged, the contacts being established, the operational readiness being enhanced through [the] PSI are all helping to create a lasting basis for co-operative action against proliferation.” The administration made the PSI a key foreign policy and defense goal in 2005, and Congress approved $50 million to help states support the initiative.[3]

On the PSI’s second anniversary, in May 2005, Secretary of State Condoleezza Rice claimed that the United States and its PSI partners had undertaken 11 successful intercepts since its inception, including the prevention of two WMD-related deliveries to North Korea as well as the transfer of ballistic missile-related and nuclear program-related materials to Iran.[4] A 12th successful PSI interdiction was subsequently announced, although the details of these interdictions were left vague. These claims of success were repeated by Robert Joseph, Bolton’s replacement, who subsequently increased the figure to “more than 30.”[5

A few weeks after the PSI’s third anniversary, representatives of 65 states met anonymously behind closed doors in Krakow to discuss its political, policy, and legal issues. The chairman of the conference, Polish Ambassador Tadeusz Chomicki, reiterated the claims of the PSI’s success, including providing a “platform” for impeding traffic in weapons of mass destruction and related materials, enhancing numerical and geographic support, and improving national capacities to interdict shipments of proliferation concern.[6] Detailed information to support these claims or even a list of countries attending the meeting were not made available. 

To be sure, the PSI and other U.S.-driven supportive efforts have improved the awareness of the danger and urgency of the problem. The focus on interdiction also has no doubt constrained some trade in weapons of mass destruction, their delivery systems and related materials or at least forced rogue traders to change their tactics. PSI exercises have increased national capacities for coordinated detection and interdiction of suspect shipments. With the United States having successfully negotiated ship-boarding agreements with the countries whose flags fly on the bulk of the world’s ships, flag-state consent for boarding to search for weapons of mass destruction has become an expectation for and of many states (but not a legal obligation). Most importantly, the PSI has evolved and metamorphosed from a focus on interdiction of ships at sea to inspection in ports, to carriage of weapons of mass destruction by aircraft, and for the United States, to disruption of financial networks involved or supporting such trafficking.

However, much water has flowed under the stern since the PSI’s early heady days of full steam ahead. The PSI’s architects and principal champions, Bolton and Joseph, are no longer in the U.S. government. Moreover, the PSI has been criticized for lack of transparency and public accountability, stretching if not violating the principles of international law, impeding legal trade, weakening the UN system, being politically divisive, diluting other nonproliferation efforts, and for all these reasons, having limited effectiveness. 

Rhetoric Versus Reality 

Because PSI interdictions are cloaked in secrecy, an assessment of the PSI must rely on an examination of publicly available information regarding specific claims for the PSI made by the U.S. government and PSI advocates. In many cases, the reality does not appear to match the Bush administration’s rhetoric.

The Limits of Support

The Bush administration claims that nearly 80 countries support the PSI, but it is unclear what “support” means.[7] The “concrete steps” for contribution to the PSI listed on the Department of State’s website[8] are rather vague and conditional. First and foremost, participating states are encouraged to commit formally to and endorse publicly, if possible, the PSI’s Statement of Interdiction Principles. Follow-up steps are also replete with conditional language such as “indicate willingness,” “as appropriate,” “might contribute,” and “be willing to consider.”

Although the State Department has posted a list of some 81 nations that have participated in PSI meetings or exercises, it is not at all clear that “participation” equates with “support” as defined by the State Department. Indeed, apparently some participating states have not publicly (or even privately) endorsed the PSI Principles. Reasons given include not perceiving the PSI as a top security priority and wanting to avoid possible reprisals as well as domestic criticism for cooperating with the United States. This reluctance in itself indicates less than stalwart support. Further, given the flexibility of cooperation, many if not most of these 80 so-called supporters would not be obligated to interdict vessels or aircraft at the behest of the United States and might well decline doing so. Thus, in a pinch, such “support” could easily evaporate.

Weak Support in Asia

Although there is indeed a growing list of nations willing to associate themselves with different aspects of the PSI on a case-by-case basis, support in Asia, a major focus of proliferation concern, is weak. Despite considerable U.S. pressure to participate fully and publicly, key countries such as China, India, Indonesia, Malaysia, Pakistan, and South Korea remain outside the “coalition of the willing.” The cooperation of others, such as Japan and Russia, is lukewarm at best.

Unsupported Claims of Success

There is insufficient public information and no objective measure of PSI success or failure. Thus it is unclear how the much-touted 12 or even 30 PSI interdictions in three years compares to efforts prior to the initiative or if an increase in successful interdictions is due to an increase in proliferation activity. The reported interdictions could actually be considered a rather poor result compared to the Stanford Database estimate of an average of 65.5 nuclear trafficking incidents per year. Furthermore, the much-touted October 2003 interdiction of WMD-related materials bound for Libya was most likely not due to the PSI, contrary to assertions by some U.S. officials. Rather, it was the result of an unrelated effort to get Libya to abandon its ambition to possess weapons of mass destruction.[9]

Limited Support Under International Law

PSI critics contend that the United States should seek specific backing for the initiative under international law, but its supporters say several measures already provide such a legal foundation. They include UN Security Council Resolutions 1540 and 1718, amendments to a relevant international maritime convention, a series of ship-boarding agreements, and the right to self-defense under the UN Charter.

Resolution 1540

In March 2004, the United States and the United Kingdom began an effort to obtain a UN Security Council resolution specifically authorizing states to interdict, board, and inspect any vessel or aircraft if there is reason to believe it is carrying weapons of mass destruction and/or their means of delivery. This was a difficult tacit admission by the United States that it needs a UN mandate to legitimize high-seas PSI interdictions. It was hoped that such a resolution would also prohibit UN member states from purchasing, receiving, assisting, or allowing the transfer of weapons of mass destruction from specified states.

The resolution that passed, Resolution 1540, was a much watered-down version of the original. For example, under a veto threat from China, the United States dropped a provision specifically authorizing the interdiction of vessels suspected of transporting weapons of mass destruction. China has questioned the efficiency and legality of the PSI as it involves interdictions, arguing that the best way to prevent WMD proliferation is through dialogue, not force.[10]

The resolution does not specifically mention the PSI and does little to strengthen its effectiveness against state-supported trafficking because it focuses on nonstate actors. Moreover, large gaps exist between obligations incurred under the resolution and the number of countries that have taken steps to meet those obligations, i.e., strengthening their domestic laws criminalizing the spread of weapons of mass destruction and enhancing their export and border controls.[11]

Finally, some states consider Resolution 1540 imbalanced because it does not address disarmament and it obliges governments to devote resources to problems they do not consider a high priority. In other words, they view Resolution 1540 as another example of U.S. hegemony and are therefore not likely to be robust in their application of it.

Resolution 1718

This resolution, drafted by the United States and Japan, prohibits the transfer to and from North Korea of nuclear, chemical, or biological weapons; their means of delivery (ballistic missiles); and related materials. This language is very similar to that used in the principles guiding PSI implementation. The United States clearly wanted to conflate the PSI with Resolution 1718 and thereby legitimize it. The resolution does require all UN member states to prevent the transfer of such material to North Korea on their flag vessels or aircraft, in theory a boost for the PSI. For compliance with these requirements, however, it merely “calls upon” states to take cooperative action to prevent illicit trafficking in such materials. It does not require them to do so.

Moreover, it clearly states that measures must be taken under UN Charter Chapter VII, Article 41, which specifically does not authorize the use of armed force. Such use of armed force would probably be necessary if a country operating under the PSI tried to interdict and board a vessel that refused to stop. Thus, the use of force in such a situation could still be interpreted as an act of war. Even Secretary of Defense Donald Rumsfeld in 2006 conceded that the PSI “has holes in it,” including the lack of a legal basis for interdiction of vessels and aircraft and confiscation of their cargo on the high seas.[12]

China was again the main obstacle to a more robust resolution. At China’s and Russia’s insistence, the authority to use military force was dropped from the draft resolution as was the requirement to check all cargo bound to or from North Korea. Although China voted for the resolution, it immediately ruled out its participation in interdiction of vessels or aircraft on or over the high seas, saying that it was not required. South Korea also demurred. Japanese Prime Minister Shinzo Abe and leading hawks in his administration support such interdictions on the high seas or in Japanese territorial waters, even though there are many inconvenient legal obstacles to Japan’s direct involvement. There have been several inspections of North Korean vessels in foreign ports under Security Resolution 1718, but there have been no reports of interdictions at sea.

Amendments to Maritime Convention

In October 2005, the International Maritime Organization approved U.S.-proposed and British-supported amendments to the Convention for the Suppression of Unlawful Acts Against the Safety of Maritime Navigation. The convention already obligates states-parties to incorporate into their domestic laws the offenses it identifies. The amendments broadened the covered offenses to include the use of a vessel as an instrument of or platform for terrorist activity; the transport of weapons of mass destruction and “any equipment, materials or software or related technology that significantly contribute to [WMD] design, manufacturing or delivery;”[13] and the transport of a person who has committed a terrorist act. Direct consent from the flag state is still required to board, inspect, or take any other action.

Moreover, there must be evidence of knowledge of intent that the material in question will be used for terrorism. Finally and most importantly, the convention and its amendments apply only to states-parties, and most states of proliferation concern are not states-parties. Moreover, few countries have yet taken legislative action to turn the amendments into domestic law.

Ship-boarding Agreements

Some argue that bilateral agreements between the United States and other states make interdiction and boarding of suspect vessels allowable under customary international law. The United States has entered into seven PSI ship-boarding agreements, with Belize, Croatia, Cyprus, Liberia, Malta, the Marshall Islands, and Panama. Together with PSI “core supporters,” these agreements cover perhaps 70 percent of the world’s commercial fleet by tonnage. The agreements use language from the PSI principles and make it easier for the United States to board and inspect vessels from these flag states reasonably suspected of transporting weapons of mass destruction, their delivery systems, and related materials. All the agreements respect flag-state consent for boarding on the high seas, although in four such agreements a lack of response by the flag state in two or four hours authorizes boarding and search for weapons of mass destruction.

Nevertheless, such interdiction, boarding, and search would not apply to flag states not party to these agreements. Freedom of the high seas and its corollary, the flag-state consent regime, remain fundamental principles of international law and cannot be overturned or eroded by the practice of a few countries over such a short period of time.

The UN Charter

A final legal argument for PSI interdictions relies on the right of self-defense in Article 51 of the UN Charter. Preemptive self-defense includes anticipatory self-defense and preventive self-defense.[14] For an action to be compatible with current international legal interpretations of anticipatory self-defense, the United States and its coalition partners would probably have to demonstrate not only that the interdicted cargo required such action because it posed a specific and imminent threat of attack on the United States or one of its allies but also that the necessity of self-defense was instant and overwhelming, leaving no choice of means and no time for deliberation.[15] In other words, a response was necessary, proportional to the threat, and the threat was imminent.[16] Otherwise, such action and rationale would be greatly expanding the traditional definition of self-defense to include preventive self-defense regarding nonimminent threats and would set a dangerous precedent that could undermine the very foundations of the United Nations.

In fact, Article 51 provides the right of self-defense only in the case of an armed attack and only until the UN Security Council “has taken measures necessary to maintain international peace and security.”[17]

The PSI’s Limited Effectiveness

Reflecting the Bush administration’s philosophical disdain for the UN, the PSI was conceived, originated, and implemented outside the UN system. In reality, it remains a U.S.-initiated and ­ driven ad hoc activity designed primarily to deter trade in WMD components and “related materials” to and from North Korea and now Iran. It is far from clear that 12 successful interdictions in two years or even 30 in three years[18] mean that the PSI is effective. State and nonstate actors that want to avoid PSI interdictions can still transport WMD components on their own flag vessels or aircraft or on those of nonparticipating states, such as Cambodia. This is particularly applicable to warships and government ships operated for noncommercial purposes, which under Article 32 of the 1982 UN Convention on the Law of the Sea have immunity from other state’s jurisdiction.

 Moreover, countries that are key to an effective PSI, such as China, India, Indonesia, and South Korea, have not publicly joined the activity despite U.S. pressure to do so, and Japan and Russia seem to be rather reluctant participants. Some states feel that the United States is applying double standards[19] and are concerned by the lack of clarity in some PSI definitions, such as what determines which states are “of proliferation concern” and what constitutes “good cause” (for interdiction), as well as the obligations linked to these vague and subjective definitions.

 The secrecy surrounding PSI interdictions and the methods employed make it difficult to evaluate its effectiveness or its legitimacy and, more importantly, the garnering of support from countries suspicious of U.S.-driven endeavors. Some fear that the United States would like to change existing international law to allow PSI interdictions on or over the high seas or to erode the regimes of freedom of the high seas and innocent passage. Others were alarmed by Bolton’s argument that such interdictions are warranted by a right to preemptive self-defense. Indeed, they do not want to see the PSI lead to instability or the weakening of the international prohibition against the unilateral use of force outside the constraints of the UN Charter. Moreover, public support for the PSI by some countries would be a domestic public liability as it would make the government appear to be the handmaiden of the United States and reliant on U.S. intelligence. 

Because finding and interdicting suspected WMD-related cargo is so difficult, the PSI relies heavily on intelligence sharing. Unfortunately, U.S. intelligence failures have been all too common and are not new. The 1993 detention of the Chinese vessel Yinhe, which was suspected of carrying chemical warfare precursors to Iran, is a specific example of faulty intelligence resulting in an unjustified interdiction.[20]

Intelligence sharing has constraints both for the provider and the receiver. For the provider of intelligence, there will have to be a careful trade-off between providing sufficient intelligence to show “good cause” and protecting intelligence methods and sources.

For the receiver that is requested to interdict, it would have to decide if the WMD material in the hands of the intended recipient constitutes a threat significant enough to warrant action.[21] It would also want to know if the intended recipient has a legitimate civilian use for the material. Further, the intelligence will probably have to pass different thresholds regarding its ability to support a decision for interdiction.[22] These thresholds will likely vary between and even within nations and with the action intended (e.g., interdiction, boarding, inspection, diversion or seizure).

In sum, the United States is unlikely to trust all PSI participant nations equally with its intelligence, and given past U.S. intelligence failures, some countries may not be willing to act on skimpy or suspect intelligence.

As is often stated by its proponents, the PSI is an activity rather than an organization, and thus it lacks an independent budget or coordinating mechanism. Although these features may enhance its flexibility, as well as the speed of decision-making and resultant action, they also constrain its capacity. Moreover, placing such emphasis on interdictions may undermine other nonproliferation efforts. 

Perhaps the greatest obstacle to PSI effectiveness is the dual-use nature of WMD materials and technologies. Few if any countries export “turn-key” weapons of mass destruction. The harsh reality is that countries and nonstate actors can build their own weapons of mass destruction from items that have civilian application. This means that it is very difficult to make decisions regarding “good cause” for interdiction and that such decisions will inevitably be politically influenced and based on who is sending or receiving the shipment. Moreover, a proliferation of interdictions of dual-use materials may hamper legitimate commerce and thus engender opposition, even from allies. 

Enhancing PSI Effectiveness

The PSI obviously has some way to go before it becomes the widely supported, effective tool its founders envisioned and its advocates desire. Indeed, for the PSI to be fully successful will require near universal support. Even if global support is forthcoming, inadequate resources, intelligence, and capacity may ensure that a significant portion of WMD-component shipments will avoid detection and air or sea interdiction.

 Most of the PSI’s shortcomings stem from its ad hoc, U.S.-driven nature outside the UN structure. Bringing it into the UN system and providing a budget for it, as advocated by a recent House of Representatives-approved bill,[23] would rectify many of these shortcomings and in the long run improve its effectiveness. One way to do this would be to seek a UN Security Council resolution authorizing the use of force for interdiction on or over the high seas and in territorial waters of weapons of mass destruction and related materials, either in specific cases or in general.

The PSI’s reach and effectiveness could also be improved by eliminating double standards, increasing transparency, and establishing a neutral organization to assess intelligence, coordinate and fund activities, and make recommendations or decisions regarding specific or generic interdictions. Such an organization, perhaps built on the 1540 Committee, if seen to be neutral, transparent, fair, and objective, could answer key questions, such as what combinations of actors and materials represent threats and what is good cause. It would also help avoid erroneous judgments and disagreements that might impede legitimate commerce or delay action. The organization would also give the PSI a concrete structure with a consistent strategy and modus operandi, as well as a budget to fill gaps in interdiction and intelligence-collection efforts. Moreover, it could ensure that PSI activities stay within existing international law or serve as a vehicle for changing it. Last but not least, it would also ensure that the effort complements other nonproliferation efforts rather than undermines them.

Mark J. Valencia is a visiting senior fellow at the Maritime Institute of Malaysia and author of The Proliferation Security Initiative: Making Waves in Asia (2006).


1. Mark T. Esper and Charles A. Allen, “The PSI: Taking Action Against WMD Proliferation,” The Monitor, Vol. 10, No. 1 (Spring 2004), p. 4.

2. John Bolton, Remarks to the First Anniversary Meeting of the Proliferation Security Initiative, Krakow, Poland, May 31, 2004.

3. “U.S. Wants Greater Co-operation in WMD Interdiction,” Middle East Newsline, March 9, 2005.

4. Donna Miles, “Proliferation Security Initiative Marks Second Anniversary,” American Forces Press Service, June 1, 2005; “U.S. Intercepts Two Deliveries of Nuclear Material for North Korea,” The Korea Herald, June 2, 2005.

5. Robert Joseph, speech, July 18, 2006.

6. Proliferation Security Initiative High-level Political Meeting, Warsaw, June 23, 2006, found at http://www.psi.msz.gov.pl/.

7. Sharon Squassoni, “Proliferation Security Initiative,” CRS Report for Congress, June 7, 2005.

8. Bureau of Nonproliferation, U.S. Department of State, “Proliferation Security Initiative, Frequently Asked Questions (FAQ),” May 26, 2005.

9. Wade Boese, “Key Interdiction Initiative Claim Misrepresented,” Arms Control Today, July/August 2005, p. 26-27.

10. Andreas Persbo and Ian Davis, “Sailing Into Uncharted Waters? The Proliferation Security Initiative and the Law of the Sea,” BASIC Research Report 2004, June 2, 2004.

11. Richard T. Cupitt, “UNSC Resolution 1540 (2004) and Its Implications,” Presentation given at American University, April 2006.

12. Burt Herman, “Searches of N. Korean Ships Sticky Issue,” Associated Press, October 19, 2006.

13. 2005 Suppression of Unlawful Acts Amendments, Article 3.

14. Anticipatory self-defense is an attack on another state that actively threatens violence and has the capacity to carry out the threat but has not yet done so. Preventive self-defense is an attack against another state when a threat is feared or suspected but there is not evidence that the threat is imminent. Daniel H. Joyner, “The PSI and International Law,” The Monitor, Vol. 10, No. 1 (Spring 2004), pp. 7-9.

15. Gerald S. Seib, “A Bush Doctrine Is Put in Jeopardy by Weapons Hunt,” Asian Wall Street Journal, Oct. 9, 2003; Robert A. Hamilton, “International Maritime Expert: Law Supports War on Terror,” The Day, Nov. 9, 2003.

16. Ibid.

17. UN Charter, Chap. VII, Art. 51.

18. “Container Ships: The Next WMDs?” The Caltrade Report, Sept. 30, 2006.

19. The United States apparently exempts suspect shipments to and from India, Israel, and Pakistan for political reasons.

20. Ye Ru’an and Zhao Qinghai, “The PSI: Chinese Thinking and Concern,” The Monitor, Vol. 10, No. 1 (Spring 2004), p. 23.

21. Based on UN Convention on the Law of the Sea, Art. 106 (“Liability for Seizure Without Adequate Grounds”).

22. Ibid.

23. “It is the sense of Congress...that the President should strive to expand and strengthen the Proliferation Security Initiative (PSI)…with a particular emphasis on...working with the United Nations Security Council to develop a resolution to authorize the PSI under international law.” “A Bill to Provide for the Implementation of the Recommendations of the National Commission of Terrorist Attacks Upon the United States,” Subtitle B - “Proliferation Security Initiative,” Sec. 1221, 110th Cong., 1st sess.

Posted: June 2, 2007


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