The presidential authority to launch a nuclear strike alone stems from the Cold War, when the US feared a Soviet missile strike against US ICBM silos; our missiles had to be launched before theirs hit, and Soviet missiles would reach targets in the US in 20-30 minutes, so there would be no time to consult a larger circle.
This is one of the reasons Former Secretary of Defense William Perry and General James Cartwright, former Commander of the US Strategic Command, cited in a letter to President Trump on October 31, urging him to abandon the ICBM leg of the triad, rather than forging ahead with an expensive full replacement ICBM arsenal. Because of the ‘use them or lose them’ logic, plus the fact that ICBMs cannot be recalled once launched, their letter identifies this leg of the triad as the most susceptible to an unintended or accidental nuclear war.
The Air Force hasn’t waited for the Nuclear Posture Review to be released this winter, already awarding contracts to Northrup Grumman and Boeing for the ‘modernized’ ICBM force, called Ground-Based Strategic Deterrent, or GBSD. (Lockheed is also in the competition – the Air Force will ‘down-select’ from three companies to two for the next phase of the program.) (ref)
“Ballistic missiles armed with nuclear warheads are enablers of the apocalypse.”