Nature abhors a vacuum, we are told, and that certainly applies to planning. What I mean is, the planning in any situation not only acquires the influence of direct intentions, but also the influence of contextual effects.
In 1945, the United States dropped two atomic bombs on Japanese cities, ostensibly to compel unconditional surrender. While I believe this is true, I also agree that President Truman was sending a message to Stalin. The side effect of that message was the all-out effort by the Soviets to get their own nuke, which was successful, and in its own side effect began a long Intelligence war.
By 1962, the fear that the U.S.A. and U.S.S.R. might destroy the world through a nuclear nightmare was an exaggerated rumor; there simply was not enough nuclear material to kill off the planet, a comforting condition lost over the next generation. The Cuban Missile Crisis concealed a deeper problem, however - proliferation of Nuclear Weapons technology, to countries like communist China, France, India, and Israel, some of whom were considered a bit less than completely stable.
Roll up to 1976. The Communists had developed their nuclear forces through two motives - fear of a US nuclear ultimatum, and as a fallback in the event of invasion, a neglected but ubiquitous fear in Communist countries. With the unexpected victory in Vietnam, however, the Communists set aside old plans and became aggressive in South America and Africa, creating or emboldening movements in dozens of countries, along the way creating dozens of international terrorist groups, like the Red Brigade and its like. They never planned on Ronald Reagan.
The significance of Ronald Reagan may never be fully understood by the average person, especially on the Nuclear level. By his election in 1980, the United States was at a low tide of influence, and many experts thought the U.S. would depend on unconventional warfare to stave off defeat in its many conflicts. Vietnam, they claimed, proved the United States could not prevent revolution, and the lack of effective conventional force diluted American influence in Europe, which was not beginning but continuing a slow surrender to Communism, by first setting up Socialist governments. The Conventional Wisdom was that the U.S. should try to get the best deal it could, while it possessed something of importance, albeit one in decline. Ronnie changed all that, drastically.
The victory in Grenada, the pressure on Cuba, the tough stance in El Salvador and Nicaragua, all were discounted because they appeared small, but they were part of a greater strategy, which countered the Communists and terrorists where they could not prevent American victory. The Achille Lauro incident, with its subsequent midair interception of the terrorists, showed not only resolve but competency, and raised the stock of American military credibility. This addressed the nuclear element, by showing the U.S. could and would act effectively, without even needing to consider a nuclear dimension.
The early theory of Nuclear Warfare, was essentially to use nukes as a trump card in reserve if your nation had them, and to chase their acquisition if your nation did not. That developed to a condition where both sides held nukes, but without a clear strategy for their use; they could kill and destroy a great deal, but were not precise enough or plentiful enough to single-handedly decide a war, and they were nasty enough to repel casual use. The proliferation issue only raised the stakes; no one who had nukes, could afford to set them aside.
With Reagan’s aggressive use of conventional forces in unconventional opportunities, the value and importance of nuclear arsenals was diluted. The Intelligence War was also in full swing, but the classification of vital data prevents full explanation of how Reagan’s CIA swung things around. Suffice it to say, that Casey at CIA and Faurer at NSA, with Bob McFarlane all through things, drove the Soviets nuts. The USA wins in Intelligence, though unreported by the press, were important factors driving Soviet acquiesence in WMD talks.
Fast forward to now. The number of nations which possess nuclear weapons capability is almost the same size as it was in 1984, an impressive feat of control. The number which possess effective arsenals is smaller still. The question most worrisome these days, is the risk of terrorist acquisition of nuclear weapons, which is worth an extended work itself, but from a military point of view, the risk is actually negligible. What’s more, increased accuracy has actually led to much smaller warheads. The question then, is how to reduce the risk of nuclear conflict by other countries, the most serious risk being the possibility of an India-Pakistan exchange, escalated by China involvement for any number of reasons. This is the real trick to the North Korea warhead question - China has carefully made no public statement supporting or condemning the issue of NK nukes, though private sources indicate that Beijing has sent clear signals to Pyongyang that if they cross certain triplines, there are no restrictions to the potential Chinese response. Ironically, both NK and the PRC are looking to the United States to resolve the impasse, even as both nations publicly decry American involvement.