Among the greatest foreign-policy dilemmas faced by former President Jimmy Carter is one that has never been publicly aired but is gaining new relevance. It concerns nuclear war, and how the U.S. government would survive it. Carter’s decisions remain classified, but documents newly declassified by the CIA, along with the archives at several presidential libraries, provide a new window into the White House’s preparations for an imminent apocalypse.

Today, such an apocalypse could be triggered by any number of nuclear-armed states, including North Korea and Pakistan. During Carter’s presidency, such anxieties were focused squarely on the Soviet Union. It was during that period that military planners in both the Soviet Union and United States began to grapple with what until then had been an unthinkable heresy: abandoning the Mutually Assured Destruction catechism that had governed global order since the 1950s and preparing for surviving an all-out nuclear war.

Carter and his White House were interested in more specific questions. If the presidency could survive after a nuclear war, what exactly would it do afterward? How could the surviving commander in chief be identified? Who would identify him? How would he fulfill the three main functions of the presidency: to be the chief executive of the government, the head of state, and the commander in chief of its armed forces?

Carter’s answers came in the form of Presidential Directive 58, which was issued in the final months of his presidency; Ronald Reagan amended those plans with his own presidential directive in 1983. Their contents inform the continuity of government plans that remain in effect for the Trump administration. They have been the object of a multibillion-dollar pastiche of programs and a magnet for conspiracy theorists around the world.
What follows is a glimpse at how the government developed some of its most closely held national-security secrets — and how the Trump administration, or any of its successors, might rely on them to survive the end of the world as we know it.