Five of the nine nuclear-armed states – France, Pakistan, Russia, the United Kingdom, and the United States – maintain written nuclear doctrines that allow for the “first use” of nuclear weapons.
Two of the nine, India and China, have long had so-called no-first-use policies, declaring that they will only use nuclear weapons in retaliation to the use of such weapons by an adversary (Indian policy allowed for the use of nuclear weapons in response to chemical or biological attack in 2003). Yet both are in the process of expanding their arsenals, which many analysts have interpreted to suggesting that they might be envisioning pre-emptive use under certain circumstances.
Kim Jong- un stated in 2016 and 2018 that North Korea will not use nuclear weapons unless “its sovereignty is encroached upon by any hostile force with nuclear weapons”.However, other statements issued by the same government, including threats of a “pre-emptive nuclear strike of justice” against Japan and South Korea, have negated the credibility of these comments.
Russian President Vladimir Putin’s apparent claim in October 2018 that Russia would not use nuclear weapons first is not reflected in Russia’s official nuclear-weapons doctrine, which explicitly stipulates that Russia would consider their use in response to the use of “weapons of mass destruction against it and/or its allies, as well as aggression against Russia with the use of conventional weapons when the very existence of the state is in jeopardy”.
The last nuclear-armed state, Israel, has not formally admitted to possessing nuclear weapons, and has thus not made clear its policy on use.
Theorists often distinguish between strategies aimed at destroying the adversary’s missile bases and other nuclear assets (“counter-force”) and strategies aimed at killing civilians and destroying the adversary’s population centres (“counter-value”). Counter-force strategies are commonly presumed to require larger nuclear arsenals and more sophisticated command and control structures than do counter-value strategies. Russia and the United States are believed to have maintained plans for both counter-value and counter-force strikes since the 1960s. The remaining seven nuclear-armed states have maintained smaller nuclear arsenals primarily structured to facilitate counter- value strikes in response to an initial attack. However, there are now signs that certain nuclear-armed states, China and India in particular, are expanding their arsenals in such a way as to enable counter-force strikes against certain potential opponents.
 H. M. Kristensen and M. Korda, “Chinese nuclear forces, 2019”, Bulletin of the Atomic Scientists 75, no. 4 (2019); H. M. Kristensen and M. Korda, “Indian nuclear forces, 2018”, Bulletin of the Atomic Scientists 74, no. 6 (2018).
 R. Smart, “North Korea will not use nuclear weapons first, says Kim Jon-un”, The Guardian (8 May 2016), at.
The Military Doctrine of the Russian Federation (2014).