# Nuclear taboo

The "nuclear taboo" refers to the claimed international norm against the use of nuclear weapons. The existence of such a taboo has wide support, but not consensus, among experts.
The taboo entails that a shared understanding exists of the illegitimacy and immorality of using nuclear weapons. It purports to explain nuclear nonuse since the end of World War II. As an explanation for nuclear nonuse, it stands in contrast to rationalist deterrence theory logics for why states do not use nuclear weapons (such as mutually assured destruction) and social theories about the unwillingness to use nuclear weapons because use violates international law.

## Definitions

The concept of a "nuclear taboo" was popularised by the academic Nina Tannenwald, who wrote an influential journal article on the concept in 1999. She defined the nuclear taboo in 2005 as "a de facto prohibition against the first use of nuclear weapons". Tannenwald remains among the most prominent advocates for the existence of this taboo.
Tannenwald has also written that:
   the nuclear taboo exhibits many, although not all, of the characteristics associated with taboos: it is a prohibition, it refers to danger, and it involves expectations of awful or uncertain consequences or sanctions if violated. Further, it is also a “bright line” norm: once the threshold between use and nonuse is crossed, one is immediately in a new world with all the unimaginable consequences that could follow. Finally, the nuclear taboo counteracts the deep attraction that nuclear weapons present to national leaders as the “ultimate weapon” and reminds them of the danger that lurks behind such weapons.
In the textbook Strategy in the Contemporary World: An Introduction to Strategic Studies the concept is defined as a view that the use of nuclear weapons "is considered so disreputable and immoral that states are reluctant to use such weapons; the use of such weapons would make the state in question an outcast, despised by its peers, including those which might otherwise be sympathetic to it".
The academic Joshua A. Schwartz has defined the taboo as being that "nuclear use is perceived as so morally abhorrent that it is not even considered by policymakers or members of the public".

## Debate over the concept

Tannenwald has stated that the norm against the use of nuclear weapons developed during the first decades of the Cold War. It was driven by the anti-nuclear movement and advocacy from governments of some countries which did not possess nuclear weapons, and aimed to stigmatise the use of nuclear weapons. The governments of the United States and Soviet Union also developed a norm of nuclear restraint following the Cuban Missile Crisis in 1962.
The authors of Strategy in the Contemporary World note that "many observers" contend that the nuclear taboo exists. However, they argue that the existence of such a taboo is unproven given that there have been "no truly hard cases in which a nuclear state chose to not use its arsenal; for instance no nuclear-armed country has chosen to allow itself to be destroyed rather than use its arsenal against an invader".
In 2024 Schwartz argued that the nuclear taboo does not exist. This is because his research has found that policy makers have seriously considered using nuclear weapons on multiple occasions. Schwartz also cites opinion polls that have found majority or near-majority public support in China, France, Israel the United Kingdom and United States for their governments to use nuclear weapons in certain circumstances.