‘Peace through strength‘ is a conservative slogan supporting military strength for the purpose of creating peaceful international relations. For supporters of the MX missile in the 1970s, the missile symbolized ‘peace through strength.’ The phrase was popular in political rallies during 1988.
The idea is a major justification cited for large militaries, and also served as the primary motivation behind the Cold War doctrine of mutually assured destruction. The logic here is that a strong military deters aggression and coercion (blackmail), and that no potential aggressor in his right mind would dare to attack or blackmail someone stronger than he is, because he knows he would be swiftly defeated if he tried to. Conservatives and neoconservatives argue that if an aggressor is irrational and cannot be deterred, he can be swiftly defeated by a large and strong standing military.
Ronald Reagan used the phrase in political campaigning during his election challenge against Jimmy Carter, accusing the incumbent of weak, vacillating leadership that invited enemies to attack the US and its allies. Reagan later considered it one of the mainstays of his foreign policy as President of the United States. In 1983, he explained it thus:
‘We know that peace is the condition under which mankind was meant to flourish. Yet peace does not exist of its own will. It depends on us, on our courage to build it and guard it and pass it on to future generations. George Washington’s words may seem hard and cold today, but history has proven him right again and again. ‘To be prepared for war, he said, ‘is one of the most effective means of preserving peace.” However, for professor or International Relations Andrew Bacevich, ‘belief in the efficacy of military power almost inevitably breeds the temptation to put that power to work. ‘Peace through strength’ easily enough becomes ‘peace through war.’