The Nunn-Lugar programme was an extraordinary success, strongly supported by Democratic and Republican presidents for more than two decades. It helped to remove nuclear weapons and fissile materials from Belarus, Kazakhstan, and Ukraine; consolidate weapon storage at a smaller number of sites in Russia; upgrade the security at those sites; and construct the Mayak Fissile Material Storage Facility, an immense, fortified warehouse that now stores thousands of nuclear warheads, as well as plutonium and weapons-grade uranium. More importantly, the Nunn-Lugar programme encouraged close collaboration between the scientific and military elite of two former enemies. The fact that no nuclear weapons went missing, amid the chaos following the Soviet Union’s collapse, can be attributed not only to the assistance provided by Nunn-Lugar but also to the patriotism of Russian officers and scientists. They could have earned a fortune by selling a nuclear weapon and, as far as we know, didn’t.

Nunn-Lugar’s achievements now have a certain poignancy. In December 2014, Congress voted to cut funding for it. And Russia announced that it would end most of its cooperative work with the United States, despite the need to upgrade security at more than 200 buildings. After leaving the Senate, Sam Nunn helped to found the Nuclear Threat Initiative, a non-profit dedicated to reducing the danger posed by weapons of mass destruction. He’s often described the effort to prevent nuclear terrorism as ‘a race between cooperation and catastrophe’. The Russian decision to stop collaborating on nuclear issues, Nunn thinks, just made the latter more likely.

it hasn’t, it won’t

On 5 April 2009, standing before tens of thousands of people in Prague’s central square, President Barack Obama gave his first major foreign-policy speech. His call for ‘a world without nuclear weapons’ was widely reported. But Obama also addressed the prospect of nuclear terrorism, describing it as ‘the most immediate and extreme threat to global security’. He promised to lead an international effort that would safeguard all of the world’s vulnerable fissile materials within four years. To fulfil that promise and reduce the risk of nuclear terrorism, Obama hosted world leaders at a summit in Washington DC, in 2010. Two more nuclear-security summits have been held since then, one in Seoul, the other at The Hague. Some progress on the issue has been made. A dozen countries have completely eliminated their stocks of high-risk fissile material, and Japan agreed to get rid of more than a thousand pounds of weapons-grade uranium and plutonium. Much more remains to be done, however. Japan still has close to 20,000 pounds of plutonium. International standards have been set for how to run nuclear reactors but not for how to secure the dangerous fissile materials that those reactors produce. And Russia has announced it will not attend the 2016 Nuclear Security Summit in Chicago.