I’m also grateful to the officials at the National Nuclear Security Administration and Consolidated Nuclear Security who spoke with me on the record and facilitated my visit to the Y-12 National Security Complex: Steven Erhart, Morgan Smith, Ray Smith, and Steven Wyatt. They do not want another security lapse at Y-12 ever to occur again.

I spoke off the record to a number of anti-nuclear activists, government officials, and retired military personnel with nuclear expertise. They know who they are, and their help was invaluable.

Frank Munger, a senior writer at the Knoxville News Sentinel, has covered the news from Y-12 for more than three decades. His reporting on the break-in and its aftermath was terrific. I’m grateful to Munger for taking me to the Scarboro Church of Christ and showing me the route that the Plowshares activists followed up Pine Ridge. The fact that the two of us were confronted, just moments after stepping onto the path, by a pair of angry church ladies reassured me about the new security measures at Y-12. With great moral authority, the women asked us to leave the property immediately – and we did.

One of the attorneys in the Plowshares case, William P. Quigley, helped me to understand not only the trial but also the legal predicament of everyone who now engages in civil disobedience. Two other defence attorneys, Judy Kwan and Marc R. Shapiro, provided me with court transcripts and details about the ongoing appeal. And Mary Evelyn Tucker, a senior lecturer and senior research scholar at the Yale School of Forestry & Environmental Studies, shared her recollections of the sentencing hearing and her family’s long friendship with Sister Megan.

I’m grateful to Warden Claude Maye and Treavor Kroger at Leavenworth Penitentiary for letting me spend time with Gregory Boertje-Obed. In a free society, being imprisoned should never lead to being silenced.

I first learned about the break-in at Y-12 while visiting the World Institute for Nuclear Security (WINS) in Vienna. WINS is a non-governmental organization dedicated to preventing the theft, diversion, or misuse of fissile and radioactive materials. Its executive director, Dr Roger Howsley, and its Academy Manager, Daniel Johnson, introduced me to many of the nuclear-security challenges now faced by governments throughout the world.

At the Nuclear Threat Initiative (NTI), Des Browne, Cathy Gwin, Corey Hinderstein, Carmen MacDougall, Joan Rohlfing, Deborah G. Rosenblum, and Dr Page Stoutland taught me a great deal about the dangers still posed by weapons of mass destruction. I’m especially grateful to Sam Nunn, the chief executive officer of NTI, for his time and his help. Nunn has probably done more than any other single person to reduce the risk of nuclear terrorism. He deserves a lot more recognition, and a few more medals, for that work.