At about half past two in the morning on 28 July 2012, three people were dropped off at the Scarboro Church of Christ, a modest brick building with a single white spire in an African-American neighbourhood of Oak Ridge. They walked across the church parking lot, made their way through a stand of trees, reached a meadow, and turned left. Up ahead, in the darkness, they could see the silhouette of a steep hill called Pine Ridge. On the other side of the hill was Y-12. All three had spent time in federal prison. They belonged to a loosely organized group whose members have been prosecuted by the Justice Department for violent crimes, sabotage, and threatening national security. The three hoped to reach the uranium-storage facility before sunrise, having carefully planned the intrusion for more than a year. But they had no desire to steal anything or make a bomb. They wanted to ‘heal’ and ‘transform’ the building with their own blood; to mark it as a symbol of evil, empire, and war; to protest against its role in maintaining America’s nuclear arsenal. Gregory Boertje-Obed was a Christian pacifist in his late fifties who painted houses for a living and worked with the homeless in Duluth, Minnesota. Michael Walli was a Catholic layman in his early sixties, inspired by the life of St Francis of Assisi to live humbly and serve the poor. And Megan Rice was an eighty-two-year-old nun, a member of the Society of the Holy Child Jesus. Carrying flashlights and backpacks, they headed towards the hill.

Not so long ago, the threat of nuclear terrorism seemed imminent. In the autumn of 2001, during an interview with a Pakistani journalist, Osama bin Laden claimed to possess nuclear weapons, and President George W. Bush’s administration invoked the prospect of mushroom clouds rising above American cities to justify its wars in Afghanistan and Iraq. ‘We judge that there is a high probability that Al Qaeda will attempt an attack using a CBRN’ – chemical, biological, radiological or nuclear – ‘weapon within the next two years,’ John Negroponte, Bush’s Ambassador to the United Nations, informed the Security Council in April 2003. ‘There is little doubt that Al Qaeda intends to and can detonate a weapon of mass destruction on US soil,’ members of a bipartisan commission on national security wrote the following year.