Livermore Forensics Science Center

The easy part: Tracing technology is getting more sophisticated. It’s the international cooperation that’s hard.

Imagine it’s the day after a crude nuclear bomb has leveled a major American city. A team of nuclear experts sifts through the blast zone on the hunt for fingerprints. But they aren’t on the hunt for victims’ identification. They’re looking for the bomb’s signature, the specific traits that will help reveal the nuclear material’s origins.

Since the beginning of the atomic age, the fear of a retaliatory attack has kept many a nuclear nation from getting too close to the launch button. But with nuclear terrorism now the paramount threat and rogue regimes able to peddle the necessary ingredients on the black market, the classic deterrence of reprisal is no longer an adequate defense.

That’s led security experts to devise a new strategy: Hold states directly accountable for leaks or illicit sales of fissile material. How? Nuclear attribution. Using sophisticated techniques such as radiochemical analysis, scientists can determine the isotopic fingerprint of elements like uranium and plutonium, even after they have been used in a detonated bomb. Then, by isolating telltale trace contaminants and using traditional law-enforcement methods, analysts can narrow down the range of original sources, providing in the process a kind of “birth certificate” for nuclear material. They could then know whether the material used in a bomb might have come from, say, North Korean or Iranian facilities.

The necessary tracing technology is rapidly developing in sophistication, largely through information sharing. For a decade, an informal international working group of scientists and law-enforcement personnel have been meeting to share forensic techniques. The methods, however, are only half the equation. The International Atomic Energy Agency (IAEA), the European Commission, and the United States have been gathering databanks of “nuclear fingerprints” from different sources, against which they can match forensic samples. Having a thorough log of the world’s fissile material would be an invaluable tool in fighting nuclear terrorism.

That advantage has generated keen interest in nuclear attribution for the war on terror. The U.S. government has formally adopted nuclear attribution as part of its National Strategy for Combating Terrorism. At the beginning of October, the U.S. National Technical Nuclear Forensics Center was opened in Washington, D.C., to coordinate tracing activities. Directly after North Korea tested a nuclear bomb, President George W. Bush invoked nuclear attribution directly when he warned that “the transfer of nuclear weapons or material by North Korea to states or non-state entities would be considered a grave threat to the United States, and [it] would hold North Korea fully accountable of the consequences of such action.”

But in order for attribution to be truly effective, states will have to work together to develop policies that hold accountable all states with nuclear facilities, not just rogue regimes in Pyongyang or Tehran. What happens, for instance, if the material used in a nuclear terror attack is traced back to France or Russia? Even countries that aren’t charter members of the “axis of evil” don’t always adequately track or report lost, stolen, or smuggled nuclear materials. Eighty percent of seizures of nuclear material cannot be matched with recorded thefts, according to the IAEA. But for nuclear attribution to work as a deterrent, all countries, even the United States, must be held liable for the harm done from their wayward nuclear material.

That doesn’t mean that Moscow or Paris should be blown up in retaliation for a nuclear blast set off in the United States by terrorists. But countries could be held legally responsible for monetary damages. The families of victims can be compensated and properties rebuilt. The cost would be enormous but repaid over time. Such a policy would not be entirely without precedent—consider Libya’s payments for the 1988 airline blast over Lockerbie, Scotland—but it would be an incentive for states to keep their nuclear stocks more secure, or avoid nuclear capabilities altogether.

The necessary first step is to develop a comprehensive agreement for establishing nuclear fingerprint sharing, perhaps even just post-blast, so that the origins of material can be accurately recorded and checked. Without the ability to match nuclear material with its country of origin, attribution loses its deterrent punch. But the prospects for this kind of multilateral coordination may not be bright: Countries are loath to give up their own nuclear information, including how they may have covertly obtained data on other countries’ programs. There is also concern over the administration of such a database, given the possibility of tampering. But these concerns could be addressed through safeguards such as encryption, fostered through material tagging, and negotiated under the umbrella of the IAEA.

Such a strategy is not without its shortcomings. It would not dissuade, say, Chechen terrorists from stealing or buying Russian fissile material when they have the opportunity. And creating a complete and credible fingerprint database would be an uphill battle against states unwilling to share information and suspicious of the motivations of those who might be doing the finger-pointing.

But if anything is clear, it is that a new nonproliferation regime is desperately needed. The current threat of deterrence is no longer adequate when so many stateless terrorist groups seek nuclear capabilities. For now, states are the only actors able to create fissile materials, so they are the ones who must be held responsible for their care. Without that accountability, the incentives for aggressively preventing theft and illicit sales are weak. Consider what happened to A.Q. Khan and Pakistan: basically nothing. And with so many new countries looking to develop nuclear reactors—not simply Iran, but Egypt, Saudi Arabia, and Turkey—making sure the right ingredients don’t fall into the wrong hands won’t merely become difficult. It will become impossible. Introducing a new degree of responsibility may be the only way to decrease the chances of the worst-case scenario.