“[My time at ACA] prepared me very well for the position that I took following that with the State Department, where I then implemented and helped to implement many of the policies that we tried to promote.”
– Peter Crail
Business Executive for National Security
June 2, 2022
U.S.-Russia Nuclear Forces and Arms Control Agreements

The Presidential Nuclear Initiatives (PNIs) on Tactical Nuclear Weapons at a Glance

July 2017

Contacts: Daryl Kimball, Executive Director, (202) 463-8270 x107; Kingston Reif, Director for Disarmament and Threat Reduction Policy, (202) 463-8270 x104

Near the Cold War’s end, leaders in Washington and Moscow made reciprocal unilateral pledges to substantially limit and reduce their nuclear weaponry, most notably their tactical or “battlefield” nuclear weapons, such as nuclear artillery shells. President George H.W. Bush initiated these commitments, collectively known as the Presidential Nuclear Initiatives (PNIs), in September 1991 in recognition of the break up of the Eastern bloc and out of concern for the Kremlin’s ability to maintain control of its vast nuclear arsenal as political changes swept the Soviet Union. By pledging to end foreign deployments of entire categories of U.S. tactical nuclear weapons, Bush hoped that leaders in Moscow would follow suit; and they did, at least in part. All Soviet nuclear weapons were reportedly successfully consolidated on Russian soil. Still, Washington alleges Moscow has not yet fulfilled all of its PNI destruction commitments. Meanwhile, Russia opposes the continued stationing of U.S. tactical nuclear gravity bombs in Europe, which the PNIs did not cover. Despite lingering concerns about each other’s tactical nuclear weapons, the two sides have not negotiated further reductions or transparency measures for these arms since the early 1990s.

U.S. Presidential Nuclear Initiatives:

On Sept. 27, 1991, Bush announced a raft of unilateral initiatives to limit and reduce the U.S. tactical nuclear weapons arsenal. Specifically, he pledged to:

  • withdraw to the United States all ground-launched short-range weapons deployed overseas and destroy them along with existing U.S. stockpiles of the same weapons; and
  • cease deployment of tactical nuclear weapons on surface ships, attack submarines, and land-based naval aircraft during “normal circumstances.” Implicitly, the United States reserved the right to redeploy these arms in a crisis.

Soviet/Russian Presidential Nuclear Initiatives:

On Oct. 5, 1991, Soviet President Mikhail Gorbachev responded to Bush’s speech with reciprocal Soviet measures. Specifically, Gorbachev committed to:

  • eliminate all nuclear artillery munitions, nuclear warheads for tactical missiles, and nuclear mines;
  • remove all tactical nuclear weapons from surface ships and multipurpose submarines. These weapons would be stored in central storage sites along with all nuclear arms assigned to land-based naval aircraft; and
  • separate nuclear warheads from air defense missiles and put the warheads in central storage. A “portion” would be destroyed.

On Jan. 29, 1992, Russian President Boris Yeltsin reaffirmed Gorbachev’s commitments and expanded on them in response to a second round of unilateral U.S. nuclear weapons cutbacks focused on strategic forces. (Following the Soviet Union’s Dec. 25, 1991 collapse, Russia assumed responsibility for the Soviet Union’s nuclear complex and arms control commitments.) Yeltsin said Russia would:

  • eliminate a third of its sea-based tactical nuclear weapons and half of its ground-to-air nuclear missile warheads; and
  • halve its airborne tactical nuclear weapons stockpile. Pending reciprocal U.S. action, the other half of this stockpile would be taken out of service and placed in central storage depots.


A precise accounting of U.S. and Soviet/Russian fulfillment of their tactical nuclear weapons PNIs is difficult because of ambiguity, then and now, surrounding the composition, size, and location of these arms. By 1991, the United States had nearly 5,000 tactical nuclear weapons deployed overseas, most of which were assigned to NATO. Estimates on the size of the Soviet tactical nuclear arsenal at that same time ranged widely from 12,000 to nearly 21,700 weapons.

The United States completed its proposed reductions and withdrawals of deployed tactical nuclear weapons in 1992. The elimination process was finished in 2003.

As a result of the PNIs, the U.S. withdrew and destroyed around 2,000 ground-launched nuclear artillery shells and short-range ballistic missiles, all TNWs on navy surface ships and attack submarines, and on land-based naval aircraft, destroyed all nuclear depth bombs, de-alerted strategic bombers, and cancelled planned nuclear systems. By the mid-1990s, the stockpile of TNWs fell to below 1,000 warheads. Between 1990 and the end of 1994 (when the START Treaty entered into force), the U.S. nuclear stockpile of active and inactive warheads fell from 21,392 to 10,979, a 50 percent reduction.

At a Dec. 21, 1991 conference at Alma-Ata, the Soviet Republics of Belarus, Kazakhstan, and Ukraine pledged to return all Soviet tactical nuclear weapons on their territories to Russia by July 1, 1992. All three states met their commitments despite the Soviet Union’s breakup four days after these pledges were made. Otherwise, Russia has released little information substantiating its PNI activities. At the May 2005 nuclear Nonproliferation Treaty Review Conference, Moscow announced that all Russian tactical nuclear weapons “are now deployed only within the national territory and are concentrated at central storage facilities of the Ministry of Defense.” In 2007, Colonel-General Vladimir Verkhovtsev remarked, “Russia particularly committed itself to removing tactical nuclear weapons from the ground forces completely. Those weapons were also cut by 50 percent in the Air Force, by 60 percent in missile defense troops and by 30 percent on nuclear submarines of the Russian Navy,” the general said.

 Still, the Department of State has publicly questioned Russia’s PNI record. Specifically, it noted in June 2005, “Russia has failed to state publicly the status of the elimination of its nuclear artillery munitions, nuclear warheads for air defense missiles, nuclear mines, or nuclear weapons on land-based naval aviation.” These concerns were not expressed in the 2017 State Department Compliance Report, however.

Current Status:

As of 2016, the United States possesses about 500 B61 gravity bombs, 150-200 of which deployed in five European countries (Belgium, Germany, Italy, the Netherlands and Turkey). As of 2017, Russia retains approximately 1850 nonstrategic weapons, all of which are stored on Russian territory.

Since the PNIs, the United States and Russia have not agreed on additional measures to share information on or limit their tactical nuclear weapons. The two countries agreed in March 1997 to explore measures relating to tactical nuclear weapons, but nothing came of this effort. In June 2005, Russia conditioned additional talks on tactical nuclear weapons to the U.S. withdrawal of its remaining nuclear weapons in Europe. The United States has said these weapons are deployed as part of NATO policy and that a decision to withdraw them would need to be taken by all alliance members. In 2005, Congress passed legislation calling on the Bush administration to investigate measures to help Russia account for and secure its tactical arms and assess whether tactical nuclear reductions with Russia should be pursued.

In 2010, the Barack Obama administration stated that it was the goal of the United States to seek further reductions in all types of U.S. and Russian nuclear weapons—strategic and nonstrategic, deployed or nondeployed—following the conclusion of the 2010 New START talks. The 2010 NATO Strategic Concept states that the goal of the alliance is to "seek Russian agreement to increase transparency on its nuclear weapons in Europe and relocate these weapons away from the territory of NATO members." officials insist that the U.S. should first withdraw all of its tactical nuclear weapons to its national territory. In the 2010 Nuclear Posture Review, the Obama Administration announced a unilateral retirement of the Navy’s stockpile of nuclear-armed submarine launched cruise missiles (SLCMs). 

In April 2010, then-Secretary of State Hillary Clinton stated that the U.S. could remove nuclear weapons from Europe in exchange for a reduction in the size of Russia’s nonstrategic nuclear weapons arsenal. In 2013, Obama gave a speech advocating for the U.S. to work with European allies and Russia to negotiate future reductions in nonstrategic nuclear weapons.

However, to date the United States and Russia have not commenced talks regarding additional cuts on nonstrategic weapons, and a range of arms control disputes threatens to continue to obstruct progress on the matter. Russia is unlikely to discuss cuts to its nonstrategic nuclear weapons arsenal until the United States removes nonstrategic nuclear forces from Europe and agrees to limitations of its ballistic missile defense program. 

Strategic Arms Control and Policy

Country Resources:

Brief Chronology of START II

Contacts: Daryl Kimball, Executive Director, (202) 463-8270 x107

Nearly a decade of efforts to bring the Strategic Arms Reduction Treaty (START) II into force ended in June 2002, a month after the United States and Russia concluded negotiations on the Strategic Offensive Reductions Treaty (SORT)

SORT stipulates a 1,700-2,200 deployed strategic warhead ceiling for both countries' nuclear arsenals. The SORT limit effectively supersedes START II's cap of 3,000-3,500 warheads for each side. For more detailed information on the START II agreement, see: START II and Its Extension Protocol at a Glance.


Presidents George H. W. Bush and Boris Yeltsin signing START II in Moscow on 3 January 1993. (Photo: Susan Biddle/National Archives)

January 3, 1993: Presidents George H.W. Bush and Boris Yeltsin sign START II in Moscow.

January 15, 1993: President Bush submits START II to the Senate for advice and consent.

June 22, 1995: President Yeltsin submits START II to the Duma for ratification.

January 26, 1996: The Senate overwhelmingly approves START II by a vote of 87-4.

March 20-21, 1997: Presidents Bill Clinton and Boris Yeltsin address a number of arms control issues during their summit meeting in Helsinki. In a "Joint Statement on Parameters on Future Reductions in Nuclear Forces," the presidents agree to extend the deadline for the elimination of strategic nuclear delivery vehicles under START II by five years and to immediately begin negotiations on a START III treaty once START II enters into force (subsequently modified to occur once START II is ratified). They also agree that START III negotiations will include four basic components: (1) a limit of 2,000-2,500 deployed strategic nuclear warheads for each side by the end of 2007, (2) measures relating to the transparency of strategic nuclear warhead inventories and to the destruction of strategic warheads, (3) extension of the current START agreements to unlimited duration, and (4) deactivation of all strategic nuclear delivery vehicles to be eliminated under START II by the end of 2003.

September 26, 1997: Codifying commitments made at Helsinki, Secretary of State Madeleine Albright and Russian Foreign Minister Yevgeny Primakov sign a protocol in New York extending the deadline for the elimination of strategic nuclear delivery vehicles under START II from January 1, 2003, to December 31, 2007. In an exchange of letters, Albright and Primakov also agree that once START II enters into force, the United States and Russia will deactivate all strategic nuclear delivery vehicles to be eliminated under the treaty by December 31, 2003, "by removing their nuclear reentry vehicles or taking other jointly agreed steps." Primakov's letter also states that Russia expects that START III will "be achieved" and enter into force "well in advance" of the START II deactivation deadline.

April 13, 1998: President Yeltsin submits the START II extension protocol to the Duma.

December 25, 1998: In response to the December 16-19 U.S.-British air strikes against Iraq, the Duma postpones a scheduled vote on START II ratification.

April 2, 1999: The Duma postpones a scheduled vote on START II ratification to protest NATO's bombing campaign against Yugoslavia, which started March 24 after Serbia refused to halt military actions against Kosovar Albanians seeking autonomy. (Moscow has historically allied itself with Serbia.)

April 14, 2000: The Russian Duma (lower house of parliament) overwhelmingly approves the START II ratification legislation 288-131 with four abstentions.

May 4, 2000: Putin signs the resolution of ratification for START II and its extension protocol. The legislation makes exchange of the instruments of ratification (required to bring the treaty into force) contingent on U.S. ratification of the 1997 extension protocol and ABM-related agreements.

December 13, 2001: U.S. President George W. Bush issues a six-month notice to withdraw from the 1972 Anti-Ballistic Missile (ABM) Treaty, stating, "I have concluded the ABM Treaty hinders our government's ability to develop ways to protect our people from future terrorist or rogue-state missile attacks."

May 24, 2002: Russia and the United States sign SORT, which calls for each country to deploy no more than 1,700-2,200 strategic warheads.

June 13, 2002: U.S. withdrawal from the ABM Treaty takes effect.

June 14, 2002: Russian President Vladimir Putin declares that Russia is no longer bound by its signature of START II, ending his country's efforts to bring the treaty into force.

Strategic Arms Control and Policy

Country Resources:

The Lisbon Protocol At a Glance

Contact: Kingston ReifDirector of Disarmament and Threat Reduction Policy, (202) 463-8270 x104

A pervasive fear surrounding the collapse of the Soviet Union was the uncertain fate of its nuclear arsenal. In addition to Russia, the emerging states of Belarus, Kazakhstan, and Ukraine inherited a significant number of nuclear weapons, raising concerns that the Soviet Union would leave four nuclear weapon successor states instead of just one. Aside from increasing the number of governments with their finger on the proverbial nuclear button, the circumstances simultaneously raised concerns that those weapons might be more vulnerable to possible sale or theft. The Lisbon Protocol, concluded on May 23, 1992, sought to alleviate those fears by committing the three non-Russian former Soviet states to return their nuclear weapons to Russia. In spite of a series of political disputes that sparked some concerns about implementation of the protocol, all Soviet nuclear weapons were eventually transferred to Russia by the end of 1996.

When the Soviet Union officially dissolved in December 1991, the newly-independent states of Belarus, Kazakhstan, and Ukraine inherited more than 3,000 strategic nuclear weapons (those capable of striking the continental United States), as well as at least 3,000 tactical or battlefield nuclear weapons. In 1991, the United States and the Soviet Union announced the Presidential Nuclear Initiatives to substantially reduce their respective tactical nuclear weapons arsenals. All dispersed Soviet tactical weapons were reportedly back on Russian soil by the end of 1992, but the strategic weapons posed a larger problem.

The United States and Russia reached a solution to this complex problem by engaging Belarus, Kazakhstan, and Ukraine in a series of talks that led to the Lisbon Protocol. That agreement made all five states party to the 1991 Strategic Arms Reduction Treaty (START), which required Washington and Moscow to each cut their deployed strategic nuclear forces from approximately 10,000 warheads apiece to down below 6,000 warheads on no more than 1,600 intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs), and long-range bombers. The protocol signaled the intentions of Belarus, Kazakhstan, and Ukraine to forswear nuclear arms and accede to the nuclear Nonproliferation Treaty (NPT) as non-nuclear-weapon states, a commitment that all three fulfilled and continue to abide by today.


Estimated Warheads in Belarus, Kazakhstan, and Ukraine in 1991


Strategic Warheads

Tactical Warheads










Sources: Robert S. Norris, “The Soviet Nuclear Archipelago,” Arms Control Today, January/February 1992, p. 24; and Joseph Cirincione, et al., Deadly Arsenals, Carnegie Endowment for International Peace, 2005, p. 366.


Basic Timeline and Provisions:

  • July 31, 1991: The United States and the Soviet Union sign START.
  • Dec. 31, 1991: The Soviet Union officially dissolves, delaying entry into force of START.
  • May 23, 1992: Russia, Belarus, Ukraine, Kazakhstan, and the United States sign the Lisbon Protocol.
    • Under the protocol, all five states become parties to START.
    • Belarus, Kazakhstan, and Ukraine promise to accede to the NPT as non-nuclear-weapon states “in the shortest possible time.”
  • July 2, 1992: Kazakhstan ratifies START.
  • Oct. 1, 1992: The U.S. Senate votes to give its advice and consent to ratification of START.
  • Nov. 4, 1992: The Russian State Duma refuses to exchange START instruments of ratification until Belarus, Ukraine, and Kazakhstan accede to the NPT.
  • Feb. 4, 1993: Belarus ratifies START.
  • July 22, 1993: Belarus submits its instrument of accession to the NPT as a non-nuclear-weapon state.
  • January 14, 1994: The Trilateral Statement is signed by U.S. President Bill Clinton, Russian President Boris Yeltsin, and Ukrainian President Leonid Kravchuk. It allows Ukraine to observe the transfer of weapons from its territory to Russia and the dismantlement of certain systems. It also commits Russia to send some of the uranium extracted from the returned warheads back to Ukraine for fuel.
  • Feb. 3, 1994: Ukraine ratifies START, rescinding conditions for ratification that it had issued in November 1993.
  • Feb. 14, 1994: Kazakhstan submits its instrument of accession to the NPT as a non-nuclear-weapon state.
  • Dec. 5, 1994: Ukraine submits its instrument of accession to the NPT as a non-nuclear weapon state.
    • The five START parties exchange instruments of ratification for START, which enters into force.
  • April 24, 1995: Kazakhstan transfers its last strategic weapon to Russia.
  • June 1996: Ukraine transfers its last strategic weapon to Russia.
  • November 1996: Belarus transfers its last strategic weapon to Russia, marking completion of Lisbon Protocol obligations.

Ratification and Implementation:


When the Soviet Union dissolved, the newly-established Republic of Belarus found itself in possession of roughly 800 total nuclear weapons deployed within its borders. Although Russia retained the warhead arming and launch codes, many worried that Belarus might attempt to take control of the weapons. Moreover, Belarusian President Alexander Lukashenko twice threatened to retain some weapons if NATO deployed nuclear weapons of its own in Poland. However, when a constitutional crisis erupted in November 1996, Lukashenko was finally compelled to finalize the transfers.

Minsk signed the Lisbon Protocol on May 23, 1992, ratified it on Feb. 4, 1993, and deposited its instrument of accession to the NPT as a non-nuclear-weapon state on July 22, 1993. By November 1996, all nuclear warheads in Belarus had been transferred to Russia.


After gaining independence, Kazakhstan, with extensive U.S. technical and financial assistance, disposed of the strategic nuclear weapons that it inherited from the Soviet Union. Kazakhstan’s 1,410 strategic warheads were deployed on several different systems, including SS-18 ICBMs and cruise missiles carried by Bear-H bombers.

Kazakhstan’s parliament ratified START on July 2, 1992. All tactical nuclear weapons had been withdrawn to Russia by January 1992. The parliament approved accession to the NPT on Dec. 13, 1993, and deposited the state’s NPT instrument of ratification on Feb. 14, 1994. The last of the Kazakh-based strategic nuclear weapons were transferred to Russia by April 24, 1995.


When the Soviet Union dissolved, Ukraine became the third-largest nuclear weapons power in the world behind the United States and Russia. Ukraine’s 1,900 strategic warheads were distributed among ICBMs, strategic bombers, and air-launched cruise and air-to-surface missiles. Although Ukrainian President Leonid Kravchuk signed the Lisbon Protocol on May 23, 1992, Ukraine’s process of disarmament was filled with political obstacles. Many Ukrainian officials viewed Russia as a threat and argued that they should keep nuclear weapons in order to deter any possible encroachment from their eastern neighbor. Although the government never gained operational control over the weapons, it declared “administrative control” in June 1992, and claimed in 1993 ownership of the warheads, citing the potential of the plutonium and highly enriched uranium they contained for creating peaceful energy.

A resolution passed by the Rada, the Ukrainian parliament, on Nov. 18, 1993, attached conditions to its ratification of START that Russia and the United States deemed unacceptable. Those stated that Ukraine would only dismantle 36 percent of its delivery vehicles and 42 percent of its warheads; all others would remain under Ukrainian custody. Moreover, the resolution made those reductions contingent upon assurances from Russia and the United States to never use nuclear weapons against Ukraine (referred to as “security assurances”), along with foreign aid to pay for dismantlement.

In response, the Clinton and Yeltsin administrations intensified negotiations with Kyiv, eventually producing the Trilateral Statement, which was signed on Jan. 14, 1994. This agreement placated Ukrainian concerns by allowing Ukraine to cooperate in the transfer of the weapons to Russia, which would take place over a maximum period of seven years. The agreement further called for the transferred warheads to be dismantled and the highly enriched uranium they contained to be downblended into low-enriched uranium. Some of that material would then be transferred back to Ukraine for use as nuclear reactor fuel. Meanwhile, the United States would give Ukraine economic and technical aid to cover its dismantlement costs. Finally, the United States and Russia responded to Ukraine’s security concerns by agreeing to provide security assurances upon its NPT accession.

In turn, the Rada ratified START, implicitly endorsing the Trilateral Statement. However, it did not submit its instrument of accession to the NPT until Dec. 5, 1994, when Russia, the United Kingdom, France, and the United States provided security assurances to Ukraine. That decision by the Rada met the final condition for Russia’s ratification of START and therefore subsequently brought that treaty into force.

For more information, see Ukraine, Nuclear Weapons and Security Assurances at a Glance.

Strategic Arms Control and Policy

Country Resources:

The Open Skies Treaty at a Glance

Contacts: Daryl Kimball, Executive Director, (202) 463-8270 x107

Signed March 24, 1992, the Open Skies Treaty permits each state-party to conduct short-notice, unarmed, reconnaissance flights over the others' entire territories to collect data on military forces and activities. Observation aircraft used to fly the missions must be equipped with sensors that enable the observing party to identify significant military equipment, such as artillery, fighter aircraft, and armored combat vehicles. Though satellites can provide the same, and even more detailed, information, not all of the treaty states-parties have such capabilities. The treaty is also aimed at building confidence and familiarity among states-parties through their participation in the overflights.

President Dwight Eisenhower first proposed that the United States and the Soviet Union allow aerial reconnaissance flights over each other's territory in July 1955. Claiming the initiative would be used for extensive spying, Moscow rejected Eisenhower's proposal. President George H.W. Bush revived the idea in May 1989, and negotiations between NATO and the Warsaw Pact started in February 1990.

Treaty Status: The Open Skies Treaty entered into force on January 1, 2002. The United States withdrew from the treaty in November 2020, and Russia withdrew in December 2021, which left 32 state-parties remaining in the accord.1

Twenty-six of the treaty’s initial 27 signatories have ratified the accord and are now states-parties. Since the treaty entered into force, Bosnia and Herzegovina, Croatia, Estonia, Finland, Latvia, Lithuania, Slovenia, and Sweden have become states-parties.

Territory: All of a state-party's territory can be overflown. No territory can be declared off-limits by the host nation.

Flight Quotas: Every state-party is obligated to accept a certain number of overflights each year, referred to as its passive quota, which is loosely determined by its geographic size.2 A state-party's active quota is the number of flights it may conduct over other states-parties. Each state-party has a right to conduct an equal number of flights over any other state-party that overflies it. A state-party's active quota cannot exceed its passive quota, and a single state-party cannot request more than half of another state-party's passive quota.

The treaty allows for multiple states-parties to take part in an overflight. The flight will count as an active flight for each state-party participating. Regardless of the number of observing states-parties, however, the overflight will only count as one passive overflight for the observed state-party.

Russia conducted the first observation flight under the treaty in August 2002, while the United States carried out its first official flight in December 2002. In 2008, states-parties celebrated the 500th overflight. Between 2002 and 2019, more than 1,500 flights have taken place.

Process: An observing state-party must provide at least 72 hours' advance notice before arriving in the host country to conduct an overflight. The host country has 24 hours to acknowledge the request and to inform the observing party if it may use its own observation plane or if it must use a plane supplied by the host. At least 24 hours before the start of the flight, the observing party will supply its flight plan, which the host has four hours to review. The host may only request changes in flight plans for flight safety or logistical reasons. If it does so, the two states-parties have a total of eight hours after submission of the original flight plan to agree on changes, if they fail, the flight can be cancelled. The observation mission must be completed within 96 hours of the observing party's arrival unless otherwise agreed.3

Although state-parties are allowed to overfly all of a member’s territory, the treaty determines specific points of entry and exit and refueling airfields. The treaty also establishes ground resolution thresholds for the onboard still and video cameras. The aircraft and its sensors must undergo a certification procedure before being allowed to be used for Open Skies in order to confirm that they do not exceed the allowed resolutions.

Aircraft: The treaty lays out standards for aircraft used for observation flights. Aircraft may be equipped with four types of sensors: optical panoramic and framing cameras, video cameras with real-time display, infra-red line-scanning devices, and sideways-looking synthetic aperture radar. For the first three full years after the treaty entered into force, the observation aircraft had to be equipped with at least a single panoramic camera or a pair of optical framing cameras. The states-parties may now agree on outfitting the observation planes with additional sensors.

Data: A copy of all data collected will be supplied to the host country. All states-parties will receive a mission report and have the option of purchasing the data collected by the observing state-party.

Treaty Implementation: The Open Skies Consultative Commission (OSCC), comprised of representatives of all states-parties, is responsible for the implementation of the Open Skies Treaty. The OSCC considers matters of treaty compliance, decides on treaty membership, distributes active quotas, and deals with any questions that may arise during the implementation of the treaty.

The 2nd Review Conference for the Open Skies Treaty was held in Vienna from June 7-9, 2010, under the chairmanship of the United States. The Conference’s Final Document paved the way for the use of digital cameras and sensors in the future by requesting states-parties consider the technological and financial aspects of converting to digital systems. The document also encouraged the expansion of the Open Skies Treaty to other countries, particularly those in the Organization for Security and Cooperation in Europe, where the OSCC is headquartered.

Images of Open Skies flights are available here.



1. Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Canada, Croatia, the Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Turkey, Ukraine, and the United Kingdom. The United States withdrew in November 2020, and Russia withdrew in December 2021. Kyrgyzstan has signed, but not ratified the treaty.

2. For example, Russia, which shares its quota with Belarus, and the United States both had quotas permitting 42 flights per year, while Portugal is only obligated to allow two flights annually. Countries are not required to exhaust their flight quotas. In 2009, the United States flew a total of thirteen flights, twelve over Russia and one over Ukraine.

3. This limit can be extended by 24 hours if the host insists that the observing party use the host's aircraft and demonstration flight is conducted.

Conventional Arms Issues

Country Resources:

The Anti-Ballistic Missile (ABM) Treaty at a Glance

Contact: Daryl Kimball, Executive Director, (202) 463-8270 x107; Kingston Reif, Director for Disarmament and Threat Reduction Policy, (202) 463-8270 x104

Negotiated between the United States and the Soviet Union as part of the Strategic Arms Limitation Talks, the now-defunct Anti-Ballistic Missile (ABM) Treaty was signed on May 26, 1972, and entered into force on October 3, 1972.

The treaty, from which the United States withdrew on June 13, 2002, barred Washington and Moscow from deploying nationwide defenses against strategic ballistic missiles. In the treaty preamble, the two sides asserted that effective limits on anti-missile systems would be a "substantial factor in curbing the race in strategic offensive arms."

The treaty originally permitted both countries to deploy two fixed, ground-based defense sites of 100 missile interceptors each. One site could protect the national capital, while the second could be used to guard an intercontinental ballistic missile (ICBM) field. In a protocol signed July 3, 1974, the two sides halved the number of permitted defenses. The Soviet Union opted to keep its existing missile defense system around Moscow, while the United States eventually fielded its 100 permitted missile interceptors to protect an ICBM base near Grand Forks, North Dakota. Moscow's defense still exists, but its effectiveness is questionable. The United States shut down its permitted ABM defense only months after activating it in October 1975 because the financial costs of operating it were considered too high for the little protection it offered.

The United States and the Soviet Union negotiated the ABM Treaty as part of an effort to control their arms race in nuclear weapons. The two sides reasoned that limiting defensive systems would reduce the need to build more or new offensive weapons to overcome any defense that the other might deploy. Without effective national defenses, each superpower remained vulnerable, even at reduced or low offensive force holdings, to the other's nuclear weapons, thereby deterring either side from launching an attack first because it faced a potential retaliatory strike that would assure its own destruction.

On December 13, 2001, U.S. President George W. Bush, who argued that Washington and Moscow no longer needed to base their relationship on their ability to destroy each other, announced that the United States would withdraw from the ABM Treaty, claiming that it prevented U.S. development of defenses against possible terrorist or "rogue-state" ballistic missile attacks. During his presidential campaign, Bush said he would offer amendments on the treaty to Russia and would withdraw the United States from the accord if Russia rejected the proposed changes. However, the Bush administration never proposed amendments to the treaty in its talks with Russia on the subject. Although of "unlimited duration," the treaty permits a state-party to withdraw from the accord if "extraordinary events…have jeopardized its supreme interests." The U.S. withdrawal took effect June 13, 2002, and the treaty is no longer in force.

What the ABM Treaty Prohibited

  • Missile defenses that can protect all U.S. or Soviet/Russian territory against strategic ballistic missiles
  • Establishing a base for a nationwide defense against strategic ballistic missiles
  • Development, testing, or deployment of sea-, air-, space-, or mobile land-based ABM systems or components. (Because of the inability of either country to verify activities behind closed doors, the development and testing ban was understood to apply when components and systems moved from laboratory to field testing.)
  • Development, testing, or deployment of strategic missile interceptor launchers that can fire more than one interceptor at a time or are capable of rapid reload
  • Upgrading existing non-ABM missiles, launchers, or radars to have ABM capabilities and testing existing missiles, launchers, or radars in an ABM mode (i.e. against strategic or long-range ballistic missile targets)
  • Deployment of radars capable of early warning of strategic ballistic missile attack anywhere other than on the periphery of U.S. or Soviet/Russian territory and oriented outward
  • Deployment of ABM radars capable of tracking and discriminating incoming strategic targets and guiding defensive interceptors, except within a 150-kilometer radius of the one permitted defense
  • Transfer or deployment of ABM systems or components outside U.S. and Soviet/Russian territory

What the ABM Treaty Permitted

  • One regional defense of 100 ground-based missile interceptors to protect either the capital or an ICBM field
  • A total of 15 missile interceptor launchers at designated missile defense test ranges
  • Research, laboratory, and fixed land-based testing of any type of missile defense
  • Use of national technical means, such as satellites, to verify compliance. (The ABM Treaty was the first treaty to prohibit a state-party from interfering with another state-party's national technical means of verification.)
  • States-parties to raise questions about compliance, as well as any other treaty-related issue, at the Standing Consultative Commission, which was a body established by the treaty that meets at least twice per year
  • Theater (nonstrategic) missile defenses of any type to protect against short- and medium-range ballistic missiles. (The ABM Treaty originally did not specifically delineate the point at which a missile defense would be considered strategic or nonstrategic. The United States and Russia negotiated and signed a demarcation agreement on this subject in September 1997. While Russia ratified the agreement in May 2000, it has never been transmitted to the U.S. Senate for its advice and consent, and therefore the agreement has not entered into force. The Bush administration's June 13 withdrawal from the ABM Treaty made the demarcation agreement moot.)
  • Either state-party to propose amendments

Missile Defense

The Strategic Offensive Reductions Treaty (SORT) At a Glance

Contacts: Daryl G. Kimball, Executive Director, (202) 463-8270 x107

U.S. President George W. Bush and Russian President Vladimir Putin signed the Strategic Offensive Reductions Treaty (SORT), also known as the Moscow Treaty, on May 24, 2002. The treaty committed the United States and Russia to reducing their deployed strategic nuclear forces to 1,700-2,200 warheads apiece. The two countries also agreed to keep the 1991 Strategic Arms Reduction Treaty (START I) in force.

This warhead limit was set to take effect and expire on the same day, December 31, 2012. The 2010 New Strategic Arms Reduction Treaty (New START) superseded SORT on Feb. 5, 2011.

Background: Bush entered the White House in 2001 vowing to cut U.S. nuclear weapons to “the lowest possible number consistent with our national security.” Similarly, Putin supported lowering deployed U.S. and Russian strategic forces to less than 1,500 warheads. At that time, U.S. and Russian arsenals each contained close to the 1991 START I limit of 6,000 “accountable” warheads apiece, but the Kremlin’s forces were projected to decline more rapidly and deeply because of financial and technical limitations.

The two presidents differed on how to pursue smaller forces. Bush advocated unilateral reductions so the United States could readily alter the size and composition of its arsenal over time and respond, if needed, to new threats. But Putin favored codifying reductions in a treaty to help preserve some parity and predictability between the United States and Russia. Facing persistent pressure from both the Kremlin and top U.S. lawmakers, the Bush administration agreed to negotiate a legally-binding accord.

Nonetheless, the final product conformed closely to the Bush administration’s predisposed positions of minimizing constraints and maintaining flexibility. On March 6, 2003, the Senate gave its advice and consent to ratification in a 95-0 vote, and SORT entered into force June 1, 2003. SORT contained only five articles and totaled less than 500 words.

Reductions: Unlike past strategic arms control agreements between Moscow and Washington, SORT did not specify which warheads had to be reduced or how reductions were to be made.

The treaty stated that the two sides would limit their strategic forces in accordance with three specific earlier statements made by Bush and Putin. On Nov. 13, 2001, Bush said, “The United States will reduce our operationally deployed strategic nuclear warheads to a level between 1,700 and 2,200 over the next decade, a level fully consistent with American security.” On the same day, Putin said, “Russia is stating its readiness to proceed with significant reductions of strategic offensive arms. That is why today we are proposing a radical program of further reductions of [strategic offensive arms], at the least by a factor of three, to the minimum level necessary to maintain strategic equilibrium in the world.” The treaty text also pointed to a statement by Putin on Dec. 13, 2001, that “A particularly important task in these conditions is to legally formalize the agreements that have been reached on further drastic, irreversible, and verifiable reductions in strategic offensive arms, which we believe should be at the level of 1,500-2,200 nuclear warheads for each side.”

These vague statements allowed each side to interpret and implement its reductions as it saw fit. The United States had stated the treaty limits the number of warheads on its “operationally deployed” intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs), as well as warheads loaded on heavy bombers or stationed at heavy bomber bases. Some spare strategic warheads stored at heavy bomber bases, however, did not count against the treaty limit. Moscow had not publicly stated what warheads it considered limited by the treaty. A 2005 State Department report noted, “Russia could use the U.S. definition…or some other counting method to quantify its reductions.”

There was no limit on how many strategic warheads the United States and Russia could keep in storage or reserve. On July 9, 2002, then-Secretary of State Colin Powell testified to the Senate Foreign Relations Committee, “The treaty will allow you to have as many warheads as you want.” Washington later announced in June 2004 that it planned to almost halve the total U.S. nuclear stockpile (deployed and non-deployed) of roughly 10,000 warheads by 2012 — a goal it achieved by 2007, leading the Bush administration to promise another 15 percent cut by 2012.

No warheads or delivery vehicle had to be destroyed under the accord. Past strategic treaties spelled out precise destruction obligations and processes for eliminating delivery vehicles to ensure that “reduced” warheads could not be quickly redeployed. No previous accords mandated actual warhead destruction, but then-Presidents Bill Clinton and Boris Yeltsin agreed in March 1997 to explore warhead destruction as part of the two countries’ next reductions treaty.

SORT contained no interim reduction levels or sublimits. The United States, however, had repeatedly stated it intended to lower its strategic warheads to 3,500-4,000 by 2007. Russia did not reveal any interim goals.

The treaty also did not regulate or constrain how deployed warheads were fielded. “Each Party shall determine for itself the composition and structure of its strategic offensive arms,” the treaty declared. In effect, this meant the United States and Russia could continue deploying multiple warheads on a single ICBM—a configuration banned by the 1993 START II accord. However, START II never entered into force, and Russia repudiated the agreement on June 14, 2002—a day after the United States withdrew from the 1972 Anti-Ballistic Missile Treaty outlawing nationwide strategic ballistic missile defenses.

Verification: SORT contained no provisions for assessing compliance. The Bush administration argued against such provisions, citing improved U.S.-Russian relations. Instead, the two sides said they would rely on the 1991 START verification regime for verifying implementation. However, START I expired December 5, 2009, three years before the SORT limits took effect. The two governments agreed in the spring of 2006 to launch a working group to address START’s expiration. The U.S. delegation to the working group was headed by Undersecretary of State for Arms Control and International Security Robert Joseph, while the Russian side was led by Deputy Foreign Minister Sergei Kislyak.

The treaty established the Bilateral Implementation Commission (BIC) as a confidential forum for discussing SORT implementation issues. The BIC was designed to meet twice per year.

In conjunction with SORT, the United States and Russia also created the Consultative Group for Strategic Security to explore additional strategic arms matters. Under this framework, the two sides formed three working groups, including one on “offensive transparency” as well as missile defense and tactical nuclear weapons. The group on offensive transparency met only four times—the last time in January 2005—before it was disbanded.

Withdrawal: Either party could withdraw from the agreement after providing a three-months’ notice of its intent to do so. Atypical of most arms control treaties, the withdrawing party did not have to justify its action.

Strategic Arms Control and Policy

Country Resources:

START II and Its Extension Protocol at a Glance

Contact: Daryl Kimball, Executive Director, (202) 463-8270 x107

U.S. President George H. W. Bush and Russian President Boris Yeltsin signed the Strategic Arms Reduction Treaty II (START II) on January 3, 1993.

START II established a limit on strategic weapons and required that reductions be implemented in two phases. This treaty would remain in force for the duration of START I, which entered into force in 1994, and would expire in 2009.

The United States ratified the original START II agreement in January 1996 but never ratified a 1997 protocol or the 1972 Anti-Ballistic Missile (ABM) Treaty succession, demarcation, and confidence-building agreements. The protocol shifted the deadline for completion of START II reductions from January 1, 2003, to December 31, 2007, due to the delay in ratification. The succession agreement formalized the former Soviet republics' status as parties to the ABM Treaty. The demarcation agreements clarified the demarcation line between strategic and theater ballistic missile (TBM) defenses.

On May 4, 2000, Russian President Vladimir Putin signed the resolution of ratification for START II, its extension protocol, and the 1997 ABM-related agreements. Russia's ratification legislation made the exchange of START II's instruments of ratification (required to bring it into force) contingent on U.S. approval of the extension protocol and the ABM agreements. Congress never voted to ratify the entire package.

Russia announced on June 14, 2002, that it would no longer be bound by its START II commitments, ending almost a decade of U.S.-Russian efforts to bring the 1993 treaty into force. Moscow's statement came a day after the United States withdrew from the ABM Treaty and a few weeks after the two countries concluded a new nuclear arms accord on May 24.

The new agreement, the 2002 Strategic Offensive Reductions Treaty (SORT), required the United States and Russia to reduce their deployed strategic arsenals to 1,700-2,200 warheads apiece by December 31, 2012, effectively superseded START II's requirement for each country to deploy no more than 3,000-3,500 warheads by December 2007. However, other key START II provisions, such as the prohibition against deploying multiple independently targetable reentry vehicles (MIRVs) on intercontinental ballistic missiles (ICBMs), were not addressed in the SORT agreement.

Basic Terms:

  • Deployment of no more than 3,800 to 4,250 strategic nuclear warheads on ICBMs, submarine-launched ballistic missiles (SLBMs), and heavy (long-range) bombers by December 31, 2004. This includes no more than 2,160 warheads deployed on SLBMs, 1,200 warheads deployed on ICBMs with MIRVs, and 650 warheads deployed on heavy ICBMs.
  • Deployment of no more than 3,000 to 3,500 strategic nuclear warheads on ICBMs, SLBMs, and heavy bombers by December 31, 2007. This includes no more than 1,700 to 1,750 warheads deployed on SLBMs, as well as the elimination of heavy ICBMs and the prohibition of MIRVs on ICBMs.
  • "Deactivation" of all strategic nuclear delivery vehicles slated for elimination under the treaty by removing their nuclear reentry vehicles (warheads) or taking other jointly-agreed steps by December 31, 2003.

Additional Provisions:

  •  START I definitions, limits, procedures, and counting rules applied to START II, except where explicitly modified.
  • Unlike START I, which substantially undercounts weapons deployed on bombers, the number of weapons counted for bombers would be the number they are actually equipped to carry for START II. Provided they were never equipped for long-range nuclear air-launched cruise missiles, up to 100 heavy bombers could be "reoriented" to conventional roles without physical conversion, which would not count against the overall limits. The reoriented bombers could be returned to a nuclear role, but thereafter could not be reoriented and exempted from limits.
Strategic Arms Control and Policy

Country Resources:

The 1997 START II/ABM Package at a Glance

Contacts: Daryl Kimball, Executive Director, (202) 463-8270 x107

In September 1997, representatives from the United States, Russia, Belarus, Kazakhstan, and Ukraine signed a package of agreements in New York designed to enhance the prospects for Russian ratification of the Strategic Arms Reduction Treaty (START) II and to clarify issues pertaining to the 1972 Anti-Ballistic Missile (ABM) Treaty. Efforts to bring the package into force were terminated, however, following the signing of the Strategic Offensive Reductions Treaty (SORT) between Moscow and Washington in May 2002, the U.S. withdrawal from the ABM Treaty in June 2002, and Russia's subsequent announcement that it would no longer be bound by its START II commitments.

The package consisted of the START II extension protocol and associated agreements, a memorandum of understanding (MOU) on ABM Treaty succession, the first and second agreed-upon statements on ABM-theater missile defense (TMD) demarcation, a confidence-building measures agreement related to TMD systems, and an agreement updating the regulations of the Standing Consultative Commission, a body composed of treaty party representatives that discusses implementing issues.

Russian President Boris Yeltsin transmitted these agreements to the Duma in April 1998. The Clinton administration stated that it would submit the START II documents, MOU on succession, and both demarcation agreements to the Senate for its advice and consent on ratification after Russia ratified START II. The Senate failed to do so after Russia approved START II and the 1997 agreements in early 2000.

A chronology of events related to START II can be found here: “Brief Chronology of START II.”

START II Protocol and Associated Agreements

  • START II Protocol: Extended the time period for the completion of START II reductions from January 1, 2003 to December 31, 2007.
  • Albright-Primakov letters on early deactivation: Upon START II's entry into force, the United States and Russia would deactivate all strategic nuclear delivery vehicles slated for elimination under the treaty (e.g. SS-18, SS-24, and MX missiles) by December 31, 2003 by "removing their nuclear re-entry vehicles or taking other jointly agreed steps." Primakov's letter also contained a unilateral statement: "Taking into account the supreme national interests of the county, the Russian Federation proceeds from the understanding that well in advance of the above deactivation deadline the START III Treaty will be achieved and enter into force." Albright's letter took note of Russia's position.
  • Joint Agreed Statement: Allowed the United States to "download" (remove warheads from) Minuteman III intercontinental ballistic missiles (ICBMs) under START II any time before December 31, 2007, the deadline for all START II-mandated reductions. Previously, the United States was required to download its Minuteman IIIs by December 5, 2001, seven years after START I's entry into force.

MOU on Succession to the ABM Treaty

  • Designated the United States, Russia, Belarus, Kazakhstan and Ukraine as the parties of the ABM Treaty. Russia, Belarus, Kazakhstan, and Ukraine would assume the rights and obligations of the former Soviet Union under the treaty. Thus they collectively would be limited to ABM deployment at a single site and a total of 15 ABM launchers at test ranges.
  • Broadened the ABM Treaty's membership because a number of ABM-related facilities required to operate Russia's ABM system were located outside Russian territory after the collapse of the Soviet Union. Belarus, Kazakhstan, and Ukraine also regarded ABM Treaty membership as a key element of their independent status. The United States viewed the MOU as important because it recognized the ex-Soviet states as bound by the treaty.
  • Although the Clinton administration argued that the ABM Treaty was in force because the power to determine succession lies within the executive branch, it agreed in May 1997 to submit the MOU to the Senate for approval in connection with the ratification of an unrelated agreement associated with the Conventional Armed Forces in Europe Treaty. However, the MOU was never submitted.

First Agreed Statement on Demarcation

  • Permitted the deployment of "lower-velocity" theater missile defense (TMD) systems (those with interceptor velocities of 3 kilometers per second or less) provided that they would not be tested against ballistic missile targets with velocities above 5 kilometers per second or ranges that exceeded 3,500 kilometers.
  • Enabled the United States to deploy the Army's Patriot Advanced Capability-3 (PAC-3) and Theater High Altitude Area Defense (THAAD) systems, as well as the Navy's Area Defense system. Previously, the United States had reviewed these systems and declared them to be treaty-compliant.

Second Agreed Statement on Demarcation

  • Prohibited the parties from testing "higher-velocity" TMD systems (those with interceptor velocities above 3 kilometers per second) against ballistic missile targets with velocities above 5 kilometers per second or ranges that exceeded 3,500 kilometers.
  • Prohibited the development, testing, or deployment of space-based TMD interceptor missiles or space-based components based on other physical principles (such as lasers) which could be capable of substituting for such interceptor missiles.
  • Allowed each side to determine its own compliance with respect to higher-velocity TMD systems. The United States had determined that the Navy's Theater-Wide Defense (NTWD) system was compliant with ABM Treaty requirements.

Confidence-Building Measures Agreement (CBMA)

  • Ninety days after entry into force, the parties would conduct an initial exchange of information about TMD systems and components covered by the CBMA: U.S. THAAD and NTWD systems, as well as the Russian, Belarussian, and Ukrainian SA-12 systems. (Kazakhstan does not possess the SA-12.). This information would be updated annually.
  • Prior to testing, parties would notify one another of the test ranges that would be used to test a system governed under the CBMA. Ten days' advance notification was required prior to a TMD system test using ballistic missile targets.

Regulations of the Standing Consultative Commission (SCC)

  • The United States and Soviet Union established operating regulations for the SCC in 1973. These regulations were revised after Russia, Belarus, Kazakhstan, and Ukraine agreed to assume the rights and obligations of the former Soviet Union under the ABM Treaty.
Strategic Arms Control and Policy

Country Resources:

The START III Framework at a Glance

Contact: Daryl Kimball, Executive Director, (202) 463-8270 x107

After President George W. Bush and Russian President Vladimir Putin signed the Strategic Offensive Reductions Treaty (SORT) on May 24, 2002, it seemed unlikely that a START III agreement would be negotiated.

SORT called for each country to deploy no more than 1,700-2,200 strategic warheads. START III proposed a limit of 2,000-2,500. The Bush administration maintained that SORT specified limits on "operationally deployed" strategic nuclear forces, a term excluding warheads on bombers and submarines under refurbishment. Since those warheads were included under START counting rules, the ceiling specified in SORT and that proposed for START III were similar. SORT did not, however, address strategic nuclear warhead destruction or tactical nuclear weapons limits, both ground-breaking arms control measures that were suggested for inclusion in START III.

During their March 1997 summit meeting in Helsinki, U.S. President Bill Clinton and Russian President Boris Yeltsin agreed on a framework for START III negotiations. At the Moscow Summit in September 1998, Clinton and Yeltsin reiterated their commitment to begin formal negotiations on START III as soon as Russia ratified START II.

Ultimately, negotiations on START III were not successful, and a treaty was never signed.

Basic Elements:

  • By December 31, 2007, the United States and Russia would each deploy no more than 2,000 to 2,500 strategic nuclear warheads on intercontinental ballistic missiles, submarine-launched ballistic missiles, and heavy bombers. Russian officials stated that they were willing to consider negotiated levels as low as 1,500 strategic nuclear warheads within the context of a START III agreement.
  • The United States and Russia would negotiate measures relating to the transparency of strategic nuclear warhead inventories and the destruction of strategic nuclear warheads, as well as other jointly agreed technical and organizational measures to promote the irreversibility of deep reductions.
  • The United States and Russia would resolve issues related to the goal of making the current START treaties unlimited in duration. 

Other Issues:

  • The United States and Russia agreed that in the context of START III negotiations, their experts would explore (as separate issues) possible measures related to nuclear long-range sea-launched cruise missiles and tactical nuclear systems, including appropriate confidence-building and transparency measures.
  • The United States and Russia would also consider issues related to transparency in nuclear materials.
Strategic Arms Control and Policy

Country Resources:


Subscribe to RSS - U.S.-Russia Nuclear Forces and Arms Control Agreements