On October 7, 2015, the Associated Press released a report [2] detailing several years of undercover investigations into Eastern European smuggling of nuclear and radiological materials. The report highlighted activity in Moldova over the last five years that involved small quantities of uranium, as well as the radioactive material cesium. The sellers, according to the report, hoped the material would find its way into the hands of Islamic extremists.

A1: In locations where governance and rule of law are weak, illicit activities tend to thrive, and illegal sales of nuclear and radioactive materials are no exception. Corruption, organized crime, and nuclear materials are a dangerous mix. Reported cases of nuclear smuggling soared in the immediate aftermath of the collapse of the Soviet Union in the mid-1990s as a result of lax security and a bad economy. There are some indications that material that entered the black market then may still be for sale today. In addition to Moldova, most states in the Black Sea region have had similar cases—including Georgia, Ukraine, Kazakhstan, and Tajikistan.

The evidence connecting nuclear smuggling with terrorist groups is more elusive. In the 1990s, the group Aum Shinrikyo had a nuclear weapons development program that did not progress very far, and some documents indicate al Qaeda interest in nuclear weapons and radiological material. For other organizations, there is little evidence regarding capabilities or intentions of terrorist organizations. An article by kidnapped journalist John Cantlie in ISIS’s glossy magazine, Dabiq, in May 2015 argued that a scenario in which ISIS could purchase a nuclear weapon (from Pakistan?) was more plausible than it had been in the past. It is hard to know whether this constitutes evidence of ISIS interest or intention, and it certainly sheds no light on the probability of success.

While experts can debate the probability of a nuclear terrorist incident, no one debates the consequences. Nuclear terrorism is considered one of the biggest threats to U.S. national security today, and the United States and many of its allies have worked hard since 2001 to reduce the risks. The Obama administration began a series of nuclear security summits in 2010 to enhance awareness of the risks and will host the final summit in March 2016 in Washington, D.C.

A2: The most recent case in Moldova involved cesium—a highly radioactive material that cannot be used in a nuclear weapon but could be paired with ordinary explosives to create a radioactive mess. This kind of “dirty bomb” is considered to be within most terrorist groups’ wherewithal, as opposed to the more technically demanding challenge of acquiring/manufacturing a nuclear weapon. A dirty bomb would disperse radioactivity, potentially contaminating a wide area and causing panic.

A3: Terrorists typically seek targets of opportunity, which is why it is so important to secure such material before it enters the black market. Over the years, a number of potential sales have been interrupted or the material confiscated during sting operations. Often, the perpetrators are arrested during the sale of sample material, raising the question whether larger quantities actually exist in the black market. To date, no dirty bomb has been used, and our capabilities globally to detect radioactive material have improved.

A4: Efforts to prevent, detect, deter, and respond to nuclear material trafficking are wide ranging. The U.S. government has spent close to $1 billion annually under the Cooperative Threat Reduction Program to eliminate the risk of “loose nukes” since the 1990s, and since 2002, U.S. allies have spent a similar amount under the Global Partnership Program. International conventions such as the Convention for the Physical Protection of Nuclear Material have been expanded over time, and countries have agreed to implement UN Security Council Resolution 1540 to criminalize actions that could give nonstate actors access to weapons of mass destruction–related technologies, material, or equipment. Internationally, the International Atomic Energy Agency offers assistance to its members to ensure the physical security of nuclear materials and tracks incidents through its Incident and Trafficking Nuclear Database. Bilaterally, countries cooperate to train border guards and strengthen export controls.

The bottom line is that it is possible to protect against the misuse of nuclear material, but it will require a shared sense of urgency and purpose in enhancing nuclear security.