Nuclear-armed missiles had recently achieved a level of speed and capability so that one power could completely disarm another in a matter of minutes. This created something called first-strike instability, in which firing first — even if you think you might be firing in error — is the only way to be sure of preventing your own obliteration.
The result was that the United States and the Soviet Union repeatedly went to the brink of war over provocations or even technical misreadings. Often, officials had mere minutes to decide whether to retaliate against seemingly real or impending attacks without being able to fully verify whether an attack was actually underway. In the logic of nuclear deterrence, firing would have been the rational choice.
That dynamic is heightened with North Korea, which is thought to have only a few dozen warheads and so must fire them immediately to prevent their destruction in the event of war.