There is a risk of intentional nuclear war either as the result of beliefs that such a war could be fought, contained and won with the victors able to survive the effects of such a war; or of belief that offence is preferable to defence: that is, that the idea of allowing the nation to be attacked and then to retaliate is completely unacceptable. The former belief does not necessarily require a first-strike plan but can arise from pre-decided retaliation against aggression by massive conventional forces using a so-called tactical or field nuclear force capability.
The NATO strategy of 'Flexible Response' was even more flexible. In the USA, decisions have also been taken to launch MX nuclear missiles immediately upon warning that a Russian attack was underway. The definition of what an attack constitutes is dangerously elastic. Whether in the case of unilateral action by NATO or the USA, or of action by their adversaries, intentional nuclear war initiated as a response is increasingly likely unless disarmament agreements can be made and kept.
Following the dissolution of the USSR, concern remains regarding the continuation of the military operations stance of the Cold War period. In Russia there is the so-called "Doomsday Device", a computerized system that would automatically launch a full-scale nuclear strike against the USA and its NATO allies after the Soviet political and military leadership had been destroyed. In 1993 the system was still operational and still being upgraded by the Russian military command. In that year an exercise had been conducted rehearsing full-scale nuclear war against the USA. In 1993 the USA still possessed an equivalent system which would activate if communication between Trident submarines and the government was lost.
In 1990 it was estimated that the risk of nuclear war was higher than at any time in the previous decade, but between regional powers rather than between superpowers.