U.S. President Barack Obama has stated that the United States will not allow Iran to obtain nuclear weapons and that “all options are on the table” to prevent this outcome. This expression is generally used as shorthand for a preventive military strike against Iran’s nuclear facilities, presumably even without international authorization or broad support and absent any imminent military threat from Iran.
The objective of such an attack would be to seriously damage Iran’s potential ability to develop nuclear weapons. In September 2012, however, more than 30 former high-ranking U.S. officials and military officers endorsed a report concluding that a sustained military strike on Iran by the United States would only set back Iran’s nuclear program up to four years and subsequently increase Iran’s motivation to build nuclear weapons to inhibit any future attack.38
A military attack against Iran’s nuclear facilities would likely prompt Iran to withdraw from the International Atomic Energy Agency, probably accompanied by an Iranian revocation of its safeguards agreement and withdrawal from the nuclear Nonproliferation Treaty. These actions would close off the most important source of information available to the international community on the status of Iran’s nuclear program and increase uncertainty over time about the extent of Iran’s nuclear activities.
A military operation targeting Iran’s nuclear capability would require a major, sustained air campaign. The target list would likely extend far beyond Iran’s 25 declared nuclear facilities and related sites to include Iran’s air defenses, command and control nodes, and means of retaliation, such as its ballistic and cruise missile forces and the naval vessels used to lay anti-ship mines. Such a military campaign would probably continue for weeks.
Beyond the strike assets, additional resources would be required for personnel recovery and post-strike battle damage assessments. A campaign of this magnitude would necessarily involve phases, allowing some Iranian assets not initially struck to be removed and hidden. Afterward, the United States would soon confront difficult decisions concerning the need to go back and attack surviving facilities or disrupt the reconstruction of those that had been destroyed.
The Iranian government’s natural inclination to retaliate in response to an attack would be reinforced by popular sentiment. Iran’s nationalistic population is overwhelmingly supportive of the country’s nuclear program and sensitive about perceived threats to national sovereignty.
Such retaliation could take a number of forms, from ballistic missile attacks against U.S. military bases in the region and the cities, ports, and oil terminals of U.S. allies in the Persian Gulf to missile and rocket attacks against Israel. One of the most vulnerable retaliatory targets would be oil tanker traffic flowing through the Strait of Hormuz. Ninety percent of the oil produced by Persian Gulf states passes through the strait, as does almost 35 percent of all seaborne-traded oil and almost 20 percent of all oil traded worldwide.
In 2006, Supreme Leader Ayatollah Ali Khamenei warned that if the United States punished or attacked Iran, then “definitely the shipment of energy from this region will be seriously jeopardized.” The most effective way to drive up oil costs would be to block the strait, halting or at least reducing the passage of shipping by laying several hundred mines in the water. Iran has a variety of platforms it could use for this task. From the first evidence that mines had been laid, maritime insurance rates and the price of oil would skyrocket, compelling the United States to undertake a mine-clearing campaign.
Given the limited number of mine countermeasure assets available and their vulnerability to Iranian attack, clearing even a relatively safe channel for passage would take several days; clearing the entire strait could take a month.
During a January 31, 2012, Senate Intelligence Committee hearing, Defense Intelligence Agency Director Lt. Gen. Ronald Burgess said the Iranians “have the capability, we assess, to temporarily close” the strait. Other experts stated that efforts to reopen the vital waterway in the event of an Iranian closure could only be accomplished as part of a major military operation, which “could quickly become a war to clear the Iranian harbors and coast of most remnants of the country’s military.”
Another vector of Iranian retaliation might be to sponsor Hezbollah and Hamas attacks against Israel. Thousands of short-range rockets of varying degrees of sophistication are available in Gaza and southern Lebanon for such action.
Iran could use surrogates to launch attacks on U.S. military forces deployed in the region, which has already happened sporadically and in varying degrees. In the wake of an unprovoked U.S. attack on Iran, the governments in Kabul, Baghdad, Islamabad, and elsewhere would be much less inclined to help provide protection for U.S. forces and more inclined to make deals with the militant opposition in Iran.
A close look at the military option reveals that it would fail at permanently halting Iran’s nuclear weapons pursuits and present grievous new challenges for U.S. foreign, domestic, and security policies, adding incalculable costs to the nation in blood and treasure.