However, on Wednesday, October 24, at 10:00 a.m., as the quarantine commenced, General Power advanced SAC’s forces to DEFCON 2, one condition short of nuclear war, the first and only time that level of nuclear alert has been instituted.

Martin J. Sherwin, Gambling with armageddon: Nuclear roulette from hiroshima to the cuban missile crisis, 1945-1962, New York, 2020, p. 379