Nuclear blackmail is a form of nuclear strategy in which an aggressor uses the threat of use of nuclear weapons to force an adversary to perform some action or make some concessions. It is a type of extortion, related to brinkmanship.
Nuclear blackmail is considered most effective when the person making the threat is unhinged and ostensibly willing to commit suicide. (See game theory)
It is generally regarded as ineffective against a rational opponent who has or is an ally of someone who has assured destruction capability. If both states have nuclear weapons, the form of nuclear blackmail becomes a threat of escalation. In this situation if the opponent refuses to respond, then one's choices are either surrender or suicide. During the Cold War, the explicit threat of nuclear warfare to force an opponent to perform an action was rare in that most nations were allies of either the Soviet Union or the United States.
In 1953, Eisenhower threatened the use of nuclear weapons to end the Korean War if the Chinese refused to negotiate. Consequently, China and North Korea signed the armistice.
The United States issued several nuclear threats against the People's Republic of China in the 1950s to force the evacuation of outlying islands and the cessation of attacks against Quemoy and Matsu, part of Republic of China.