During the Cold War, nuclear deterrence failed to thwart crises, which were subsequently solved with good, old politics.
We may owe thanks for the absence of war (other than proxy) during the Long Peace -- aka the Cold War -- between the United States and the Soviet Union less to nuclear deterrence, as is commonly assumed, than to the "underlying politics." That's a thesis beginning to gain credibility which Francis J. Gavin presents as well as anyone (though I've just begun the book) in Nuclear Statecraft: History and Strategy in America's Atomic Age (Cornell University Press, 2012).
Theories about nuclear weapons, he writes (my additions bracketed):
… were based on a certain view of the world: that the international system was no longer solely driven by geopolitical competition between the great states. While these drives still mattered, international relations were now shaped by the existence of and interaction between rival nuclear forces. The weapons themselves -- their lethality, their numbers, their deployments -- drove the politics, not the other way around. The interaction could produce outcomes -- arms races, dangerous crises, and even inadvertent war -- separate from the political sources of the rivalry. These theories implied that the most effective policy might not be focusing on the underlying political dispute between rivals but to control their [nuclear] weapons and their interactions. [In part, it] meant that mutual efforts had to be made to limit dangers and to negotiate, not about the core geopolitical issues driving the dispute, but control of the weapons themselves.
"This is an extraordinary way of viewing international relations," Gavin continues. But, he asks, "does it accurately reflect the way the world works?" He then attempts to answer his own question. (Emphasis added.)
It is interesting to reflect on how rarely the ups and downs of the superpower geopolitical competition mirrored the movements of the arms race. The Soviets pushed the United States aggressively on the issue of West Germany's military status by threatening West Berlin's viability at a time when the USSR was not only weak but potentially open to a US first strike in the late 1950s and early 1960s. The Soviets left West Berlin alone after 1962, even as the US nuclear superiority that arguably helped protect the city disappeared. Why? Because the core geopolitical questions surrounding West Germany's military and political status were resolved, largely to the Soviet Union's satisfaction. In fact, it is very hard to find any evidence that … the Soviets ever considered launching a "bolt from the blue" against the United States.
Ward Wilson also approached the failure of deterrence in the Berlin crisis of 1948. In his book, Five Myths About Nuclear Weapons (Houghton Mifflin Harcourt, 2013), about which we recently posted, he writes:
Historians debate whether the redeployment of [nuclear weapons-capable] B-29s to England successfully deterred the Soviets. But few ask how Stalin could have initiated the crisis in the first place. When he ordered access to Berlin cut off, the United States had a monopoly on nuclear weapons. (the Soviet Union would not explode its first nuclear weapons for another year). Cutting off access to Berlin carried with it a significant risk of war. Where two large armed groups confront each other in a narrow space, there is always the possibility of accidental escalation. Or escalation could have been intentional. One of the options considered by Washington during the crisis was sending an armored column to force its way up the autobahn to Berlin. Given the risk of provoking a nuclear war and the U.S. nuclear monopoly, why wasn't Stalin deterred from initiating the blockade? If the risk of nuclear war deters, why did Stalin start a crisis that could have led to the use of nuclear weapons against his country?
In other words, politics often proceed independently of considerations of the threat of a nuclear attacks. Meanwhile, far from lending clarity to international relations, nuclear deterrence just creates another obstacle and adds another layer of complexity to world peace.