As the credits at the end of the movie roll down, the movie creators ask the world's governments to consider the consequences of nuclear war, pointing out that the images in the movie did not capture the full breadth of horror that these weapons can wreak. Fortunately, in the sixty years since Hiroshima and Nagasaki, nations and regimes around the world have kept such images in mind. The United States and the Soviet Union blinked during the Cuban missile crisis in 1962, while more recently, India and Pakistan came close to the brink in June 2002 and stepped back. Every one of these regimes realized that there was no such thing as victory in a nuclear war.

Countries have learned this lesson well because they have a return address. Thus a nuclear attack by Iran, North Korea or Syria on the United States is highly unlikely. Those regimes simply wouldn't want Teheran, Pyongyang or Damascus to suffer devastating nuclear retribution. Meanwhile, terrorist groups that are sponsored by nation-states are kept on a tight leash, knowing that evidence leading back to the sponsoring state would result in untoward consequences towards that country. Thus some of the most dangerous international terrorist groups such as Lashkar-e-Toiba or Hezbollah have not used nuclear weapons or devices as part of their terrorist arsenal, even though these groups are linked closely with regimes that either possess nuclear weapons or have access to materials that could be used to create crude nuclear devices.

No such constraints hold back individuals or small groups with no specific links to regimes. Imagine the consequences if the Madrid terrorist cell which carried out the train bombings last March had managed to get its hands on a nuclear weapon, a crude nuclear device or a so-called "dirty bomb". The Madrid cell consisted of men of Egyptian, Moroccan and Tunisian descent coming together in Spain to plot the attack. The investigation of the cell has identified links to individuals in Netherlands, Syria, Morocco, and France--but not any government. If one such cell decides to resort to nuclear terror, there is no return address, no regime to pull its strings tight, no way to deter it.

It is such fanatic trans-national terrorist cells, many that are being inspired by the Iraq war, that could be slipping under the radar of U.S. policy makers, who are still operating in the Cold War framework of looking at countries, and not trans-national groups, as enemies. Seen through the Cold War prism, Iran is one of the most significant threats for the United States, and thus "all options are on the table" to dissuade Iran from developing nuclear weapons capability. While in the State Department, John Bolton, the Bush administration's nominee to become UN ambassador, demanded that the United States be ready for attacks on Iran if sanctions against its nuclear program were not ordered by the UN. Such talk may not be simply bluster: according to Seymour Hersh and Scott Ritter, the United States may be preparing for massive strikes on Iran as early as June 2005.

The Bush administration has denied that it intends to attack Iran. An attack on Iran would be as momentous a decision as was the one taken to overthrow Iraq. Will the gains from the degradation of Iran's nuclear and military capabilities, and perhaps the overthrow of the mullahs overcome the potential instability that would result from such an action? Given the problems in post-war Iraq, it is fair to question whether the Bush administration has done a careful evaluation of the consequences of an attack on Iran.

A nuclear Iran would be harder to deal with in terms of pressure on its terrorist apparatus, but not much harder than has been in the case of Pakistan, which despite possessing dozens of nuclear weapons, had to tone down its sponsorship of terror under intense U.S. pressure. Iran is highly unlikely to use nuclear weapons against a nuclear power such as the United States or Israel, or to provide them to a terrorist group, because the Iranian regime and its people don't want to live the "Day After".

On the other hand, an attack on Iran is likely to add Shia Muslims to the growing number of Islamists around the globe vowing vengeance against the United States. Shias in Iraq, other Middle Eastern nations, and the rest of the world, could potentially join hands with the Salafist Sunnis such as Osama Bin Laden who have been preaching hatred for the west and the United States. The Pakistani military has a significant number of Shia officers, and anger over an attack on Iran, particularly if Pakistani cooperation is critical to the operations, could lead them to collude with terrorist groups in a bid to overthrow the government. In a nation already replete with Islamic extremism and an arsenal of nuclear weapons, such considerations must be taken very seriously.

The chaos in the aftermath of the Iraq invasion resulted in the extensive theft of high explosive materials such as RDX and HMX from Iraqi military installations. During or after an attack on Iran, nuclear materials and components could find their way into the hands of terrorists who are no longer under the control of the Iranian government.

A CIA analysis released a few weeks before the Iraq invasion had postulated that Saddam Hussein could provide WMDs to terrorists if he believed his regime was about to fall. Fortunately for the United States and the world, Saddam's WMD capability only existed in the imaginations of Iraqi expatriates and their neoconservative allies. Unlike Saddam Hussein’s Iraq, Iran has an extensive and advanced nuclear weapons program. An invasion of Iran, which threatens to topple the current regime, might prompt some of the more extremist figures in the regime to provide nuclear components to terrorists as a parting gesture of revenge.

Thus an invasion of Iran might simply swap a threat that can be deterred for a broader, undeterrable and less detectable threat. A missile launch out of Iran would be traced rapidly to its point of origin, and prompt massive retaliation against the nation. On the other hand, a suicide terrorist cell that gets its hands on nuclear materials could potentially build a crude nuclear device and use it within the United States without worrying about retaliation. In today's post-Cold War world, the latter threat is much more likely to materialize.

A protracted dialogue with Iran on security issues could allow the United States to mitigate risks inherent in Iran's nuclear program. Before pulling the trigger on yet another attack on a Middle Eastern nation, the Bush administration must do what it did not do prior to the Iraq invasion: objectively evaluate the consequences of such an action, and judge whether alternatives to military action can better secure America.

Subodh Atal is an independent foreign policy analyst with an interest in U.S. grand strategy and nuclear proliferation.