In its most recent report on Iran, the International Atomic Energy Agency (IAEA) argues the country may be close to being able to develop a nuclear weapon. The agency also claims that important technical help was provided by an outside expert, identified by other sources as Vyacheslav Danilenko, a researcher who, until 1989, had worked for three decades at a leading Soviet nuclear weapons research and design institute.

In its most recent report on Iran, the International Atomic Energy Agency (IAEA) argues the country may be close to being able to develop a nuclear weapon. The agency also claims that important technical help was provided by an outside expert, identified by other sources as Vyacheslav Danilenko, a researcher who, until 1989, had worked for three decades at a leading Soviet nuclear weapons research and design institute. Danilenko denies helping Iran with its nuclear program and says that his work at the All-Russian Scientific Research Institute of Technical Physics (VNIITF) was not connected to nuclear weapons.

A rogue Soviet nuclear expert helping Iran build a weapon is something the United States has feared since the end of the Cold War. And it has been a reasonable fear. As the Soviet economy crashed, even weapon scientists faced potential layoffs, salary delays, and low wages. The United States set up cooperative employment programs to discourage poor ex-Soviet nuclear scientists from selling their skills to would-be proliferators. Since then, the United States has worked to contain proliferation by re-employing experts with skills relevant to weapons of mass destruction (WMD) — this effort has expanded to Iraq and Libya, and some in Washington hope to include North Korea and one day Pakistan.

During the 1990s, the United States created five main programs, each of which was tasked with reducing the proliferation threat of WMD knowledge from the former Soviet Union. The Departments of Defense, Energy, and State housed these programs, and collectively they formed a piece of what is known as Cooperative Threat Reduction. These programs were supposed to focus on scientists with weapons skills. Some efforts focused on providing temporary income through short-term research contracts, and others tried to retrain and then re-employ nuclear experts in non-weapons jobs, ideally in the commercial sector. These efforts faced the same problem that is at the root of the current controversy over Danilenko: How do you determine who is a nuclear weapons scientist? And, how do you identify the weapons expert who is willing to proliferate?

When the Soviet Union first collapsed, the legacy of the Cold War meant that it was not possible to target specific WMD experts for nonproliferation cooperation. Russia was reluctant to provide a list of its WMD scientists and their skills, mostly for national security reasons. Instead of insisting on such a list, which might have stalled cooperation indefinitely, some US programs avoided the issue while others adopted shortcuts for judging whether Soviet scientists seeking funds from these redirection programs were WMD experts.

For example, some programs relied on the “trickle-down effect.” For its re-employment initiatives, the US Defense Department worked with mostly ex-Soviet conventional weapons institutes, reasoning that successful personnel conversion here would set an example and encourage WMD institutes to be involved in later conversion efforts. An Energy Department program funded community development projects and job creation for anyone living in one of Russia’s closed nuclear cities, which were home to the main nuclear weapons research and design institutes. The program’s rationale was that improving the general standard of living for weapons experts and their families would, in turn, discourage proliferation.

Other US programs that tried to focus more directly on WMD experts adopted the “self-identification” shortcut. Former Soviet scientists and technicians were asked to complete a short standardized checklist to identify their weapons-relevant knowledge. But few if any efforts were made to validate these claims. Moreover, there were incentives to exaggerate. Former Soviet WMD institutes valued the overhead, equipment, and other resources they got through participation in US programs — and institute managers knew that projects were more likely to be approved if they involved more people with important weapons-relevant skills.

Some US projects used age as a determination of weapons credentials. The reasoning was that a weapons scientist was any person who worked at an institute with some WMD function, and who was old enough to have been employed during Soviet times. Another program simply identified anyone with an advanced degree in biology as a potential biological weapons scientist.

There were other gaps. The programs only focused on experts who remained employed by their institutes — Danilenko, for example, would not have been eligible since he had left VNIITF. Moreover, even if he had stayed and if a new job had been successfully created for him by a US program, no one kept tabs on whether that job continued to exist after US involvement ended.

US programs were even less able to successfully identify scientists at risk of proliferating. The programs tended to operate under the assumption that a scientist would proliferate by moving to another state. As a result, there was insufficient attention to internet communications or to what scientists presented at conferences in places like Iran.

Over time, these shortcuts and assumptions, driven in part by an effort to show results, had two serious consequences for US nonproliferation efforts. One is that the United States had few ways to determine if its programs were reaching the most proliferation-prone scientists. The second is that at least half of its program resources, and probably more, went to people who had no skills relevant to biological, chemical, or nuclear weapons.

The Danilenko saga casts an important light on some of the problems experienced by US programs. It is not necessarily an easy task to determine whether someone is a WMD expert, and it is even more difficult to determine if that person is inclined to sell his or her skills to states or non-state groups that seek such weapons. But as the United States pursues its efforts beyond the former Soviet Union to stop the proliferation of WMD knowledge, it should look more closely at the history of these programs and the rules and assumptions they followed as they implemented their efforts. Doing so will increase not only the efficiency with which resources are expended, but the certainty that programs are reaching the WMD experts of most concern.