03/07/2007 01:31 pm ET | Updated May 25, 2011

The Awful New Arithmetic of the Atomic Bomb

"We are racing towards an unprecedented nuclear catastrophe." That's how former Clinton Administration Defense Secretary William Perry put it yesterday in a speech at UCLA. "Our greatest threat is a terrorist nuclear strike. A primitive bomb could result in 100,000 deaths and huge economic, social, and political costs." Perry warned that "Al Qaeda is trying to get a nuclear bomb and if they get them they will use them. But the good news is they cannot make them from scratch. They must either buy or steal a nuclear bomb or a nuclear material. We can stop that from happening."

So what advice exactly did Perry offer the Bush Administration to stop that from happening? Speaking at the UCLA conference on emerging nuclear threats, Perry said "I do not know how we can deter a group that uses suicide as a primary tactic. But we can deter the nations that supply the weapons and material that supply the terrorists. We can offer clear, unequivocal statements that we will hold the state responsible even if they do not deliver the bomb." By that he meant that we should warn countries of the consequences of supplying nukes to terrorists and then follow through with an attack on states that sponsor a nuclear strike. Call it "supply-side nuclear retaliation."

Just one little problem: nuclear forensics. On the morning after, just how do you do forensics on ground zero to identify the source? After a nuclear strike the will to respond will be overwhelming. But in order to retaliate in kind, we will need more than what the nuclear crime scene investigators can provide.

One could, I suppose, go on hunches. If Israel is subjected to a nuclear terrorist attack, the candidates for state sponsorship are a universe of one. Is that enough for a nuclear response? And, as Perry noted, if Iran and North Korea join the nuclear club, then the non-proliferation dam will have broken. Japan and South Korea will follow suit, and a Shia nuke will lead to a Sunni nuke in the hands of Egypt and Saudi Arabia. If a half dozen more countries join the nuclear club, then tracing the source of nuclear terrorism will become ever more complex.

Conspicuously absent in Perry's speech was any discussion of law. The Security Council was mentioned precisely zero times in his address. And the niceties of the legal limits of self-defense were ignored. Perhaps that is as is it should be. The law recognizes an inherent right to self-defense following an armed attack. But against whom? International law offers little guidance in how a state can respond when the suitcase nuke does not have a return address.

My impression after hearing Perry speak is that we must calculate the awful new arithmetic of the atomic bomb. The nuclear risk we face today is the exact opposite of the one President Eisenhower faced almost fifty years ago. At that time Eisenhower said, "Should an attack be launched against the United States, our reactions would be swift and resolute. But ... for me to say that the retaliation capabilities of the United States are so great that such an aggressor's land would be laid waste, ... while fact, is not the true expression of the purpose and the hopes of the United States. To pause there would be to confirm the hopeless finality of a belief that two atomic colossi are doomed malevolently to eye each other indefinitely across a trembling world.... Surely no sane member of the human race could discover victory in such desolation." The specter of nuclear terrorism today is that certain members of the human race seek victory in just such desolation.