Preventing a terrorist mushroom cloud. (Up Front).

The scenes of the hijacked planes crashing into the World Trade Center, the Pentagon, and in Pennsylvania are nightmare images of unspeakable horror that will forever be a part of our reality.

But imagine another nightmare: that of a mushroom cloud rising over a U.S. city. This is a threat Americans can no longer ignore. Terrorists have demonstrated their willingness to attack U.S. cities and the possibility of them doing so with nuclear weapons cannot be ruled out. After September 11, citizens and leaders alike should be better able to understand the seriousness of a nuclear threat.

The attacks on the World Trade Center and the Pentagon were powerful warnings. They signal that determined terrorists are prepared to sacrifice their lives to harm us, that future attacks could involve weapons of mass destruction, and that nuclear dangers are increasing because of terrorist activity.

Our leaders have failed to grasp that our present nuclear weapons policies contribute to the possibility of nuclear terrorism against our country. We simply aren't doing enough to prevent nuclear weapons or weapons-grade nuclear materials from falling into the hands of the wrong people.

In 1998, India and Pakistan both demonstrated their nuclear capabilities. In light of the civil unrest inspired by U.S. military action against the Taliban, what if the Pakistan government fell to extremists linked to the Taliban, thus putting nuclear weapons into the hands of a regime that might well support and harbor terrorists?

A U.S. blue ribbon commission, headed by former Senate Majority Leader Howard Baker, has called for spending $3 billion a year over the next ten years to maintain control over the nuclear weapons, nuclear materials, and nuclear scientists in the former Soviet Union. Yet, the Bush administration has proposed funding cuts for this program from $1.2 billion to $800 million this year.

The mad nuclear arms race during the Cold War, and the paltry steps taken to reverse it since, have left tens of thousands of nuclear weapons potentially available to terrorists. Today, there is no accurate inventory of the world's nuclear arsenals or weapons-grade fissile materials suitable for making nuclear weapons. Estimates have it, however, that there are currently more than 30,000 nuclear weapons in the world. We simply don't know whether these weapons are adequately controlled or whether some could already have fallen into the hands of terrorists.

Osama bin Laden claims to possess nuclear weapons. His claim is feasible. Former Russian Security Adviser Aleksandr Lebed has stated that some eighty to 100 suitcase-size nuclear weapons in the one kiloton range are missing from the Russian arsenal. This claim was reiterated by Alexey Yablokov, an adviser to former Russian President Boris Yeltsin.

More than ten years after the end of the Cold War, the United States and Russia still horde more than 10,000 nuclear weapons--each country with a total of some 4,500 weapons on hair-trigger alert. Russia has been urging the United States to move faster on START 3 negotiations to reduce the size of the nuclear arsenals in both countries, but U.S. leaders have been largely indifferent to their entreaties.

In November 2001, President Bush announced that the United States was prepared to reduce its arsenal of long-range nuclear weapons to between 2,200 and 1,700 over the next ten years. Russian President Vladimir Putin indicated Russia would make commensurate cuts. These steps are in the right direction, but they still indicate reliance on Cold War strategies of deterrence. They also don't address tactical or battlefield nuclear weapons, which are the most likely weapons to be used and to fall into the hands of terrorists.

The Bush administration's primary response to the nuclear threat has been to push for a national missile defense shield which would cost billions of dollars--the technology of which is unproven and which would, at best, be years away from implementation. A missile shield would likely do irreparable harm to U.S. relations with other countries, particularly those we need to join us in the fight against international terrorism.

Large nuclear arsenals, measured in the thousands, on hair-trigger alert are Cold War relics. They don't provide deterrence against terrorist attacks. Nor could a missile shield have prevented the terrorist attacks against the World Trade Center or the Pentagon--or protect against future nuclear terrorism.

From the outset, the Bush administration's foreign policy course has been based on unilateral U.S. actions and indifference, bordering on hostility, to international law. Since September 11, however, the administration seems to have recognized that we cannot combat terrorism unilaterally--that the United States must change its policies and embrace multilateral approaches in order to defeat terrorism, as well as many global problems, including the control and elimination of all weapons of mass destruction.

The complete elimination of nuclear weapons can no longer be a back-burner, peace-activist concern. It is a top-priority security issue for us all, and it will require U.S. leadership to achieve.

David Krieger, an attorney and political scientist, is president of the Nuclear Age Peace Foundation. Additional articles on nuclear dangers and other critical issues of peace may be found at the foundation's website at www.wagingpeace.org.