President Dwight D. Eisenhower began the contingency process in 1958, via form letters to selected business leaders, so that the federal government could continue in the event of a nuclear war. Successive presidents have gone the executive order route; most modifications have remained veiled in secret. These plans are sometimes known as "shadow government" or "government-in-waiting" -- a readiness to take over government operations after a catastrophic event.
President Reagan, in 1988, noted that elements of these plans also vest their authority in the Reorganization Plan No. 1 of 1958 (72 Stat. 1799), the National Security Act of 1947, as amended, the Defense Production Act of 1950, as amended, and the Federal Civil Defense Act, as amended.
According to the FAS, the end of the cold war brought about a reduction in importance of the COOG in the early 1990s.
However, these plans -- also known as a shadow government -- achieved some press attention post-9-11. In March 2002, media reported that "75 or more senior officials [had] been living and working secretly outside Washington since Sept. 11 in case the nation's capital is crippled by terrorist attack." Congressional leaders of both parties said that they were unaware of these contingencies.
And in 2004, Atlantic Monthly reported that "[d]uring the Reagan era Dick Cheney and Donald Rumsfeld were key players in a clandestine program designed to set aside the legal lines of succession and immediately install a new 'President' in the event that a nuclear attack killed the country's leaders."
Given that one of these men remains in leadership in this White House, and implemented parts of Reagan's Armageddon Plan on 9-11-2001-, you might consider reading the details in that article.
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