While an unhealthy organism may either act in ways it (accurately or inaccurately) understands to be in its best interest, or actively seek to self-destruct, any healthy organism will act in its own best interest. It follows, then, that a given healthy nation should take stock of itself, then chart a course to procure as prosperous a future for itself as possible. With this in mind, we may reasonably imagine that, like the US (well, at least arguably), other nations are working for their own best interest. This is where the logic breaks down, because the actions of nations are guided its leaders, and those leaders do not always act in the best interest of the nation itself. This being the case, the next best step is to determine what the leadership of a given nation is likely to see as being in its own best interest - sometimes that will match with what is best for the nation at large, and sometimes leadership is concerned only with a smaller unit within that nation. Once this determination is made, one might begin evaluating some of the ways in which the leadership in question will go about achieving its desired end. We can then consider whether they have the means to achieve their goals, the allies to support them, or even the motivation to undertake certain courses of action. From George Kennan's Long Telegram of 1946, to the Team B Report approved by Papa Bush under the Ford administration in 1976, we see painstaking efforts to evaluate our opponents, determine their objectives, and assess their capabilities with regard to meeting those objectives.
Kennan stressed containment due to the notion that the Soviets under Stalin, much like North Korea under the various 'Kim' thumbs, needed to construct a hostile external world in order to legitimize their brand of autocratic rule as a protective measure against the evil world beyond their borders. While he later explained that he didn't suspect the Soviets of wishing to launch an attack on the US at the time, Kennan was not explicit on this point when he basically said that if/when Soviet leadership confronted the US with dangerous hostility anywhere in the world, the US should seek to contain the Soviets in order to prevent expansion. This led to a certain amount of alarmism due to the idea of a Soviet threat.
This alarmism was fueled by the Team B Report, which consisted of assessments by Richard Pipes, Daniel O. Graham, Thomas Wolf, John Vogt, William Van Cleave. These analysts indicated that the Soviets were not chiefly interested in a peaceful coexistence and simply reacting defensively to the threat posed by the US; rather they were more oriented toward offensive strategies and were likely to become increasingly aggressive as their power expanded. According to this report, the Soviets were not buying into the idea of mutually assured destruction; the goal of the Soviet Union was to achieve nuclear first strike capability under the assumption that they could win a nuclear war. More fuel for the alarmist fire.
In John E. Mueller's Atomic Obsession: Nuclear Alarmism from Hiroshima to Al-Qaeda, Mueller basically explains that we live in a kind of irrational nuclear mania, ever fearing that the entity which has more or less replaced the Soviets as the US' most reviled foe: terrorists, will access these weapons. Mueller explains why he believes terrorists are unlikely to procure nuclear weapons, and that much like during the Cold War, this nuclear phobia drives us to make policies and set budgetary priorities that do not mesh with reality.
In what appears to be a refusal to learn from our past mistakes, and instead of examining the facts regarding practical nuclear capabilities, we indulge in an almost frantic awe of the power of these magical, mystical scientific innovations. Playing up their capabilities may be beneficial for the purpose of deterrence, for those who are believers in deterrence theory, but for those who prefer to calmly examine reality in an effort to more reasonably plan according to a set of plausibly likely scenarios, it is probably preferable to consider things less zealously. By no means should we undermine the considerable and formidable power of nuclear weapons, but we must awaken from the potent nuclear spell we're under. We need to come fully to our senses and measure nuclear capabilities and our response to them as calm, detached, objective observers.
While it makes sense to anticipate that other entities will use the tools at their disposal to their advantage, which will sometimes be at odds with our own interests, we must undertake measured consideration of the goals of our opponents, whether they have the means to achieve those goals, whether they have (or need) the right allies to support them, and whether they have the motivation to undertake certain courses of action.