No first use

A no first use (NFU) policy refers to a commitment by a nuclear power not to initiate the use of nuclear weapons. Such a pledge would allow for a unique state of affairs in which a given nuclear power can be engaged in a conflict of conventional weaponry while it formally forswears any of the strategic advantages of nuclear weapons, provided the enemy power does not possess or utilize any such weapons of their own. The concept is primarily invoked in reference to nuclear mutually assured destruction but has also been applied to chemical and biological warfare, as is the case of the official WMD policy of India.

China and India are currently the only two nuclear powers to formally maintain a NFU policy, adopting pledges in 1964 and 1998 respectively. Both NATO and a number of its member states have repeatedly rejected calls for adopting a NFU policy, as during the lifetime of the Soviet Union a pre-emptive nuclear strike was commonly argued as a key option to afford NATO a credible nuclear deterrent, compensating for the overwhelming conventional weapon superiority enjoyed by the Soviet Army in Eurasia. In 1993, Russia dropped a pledge against first use of nuclear weapons made in 1982 by Leonid Brezhnev, with Russian military doctrine later stating in 2000 that Russia reserves the right to use nuclear weapons "in response to a large-scale conventional aggression". Pakistan has also made similar statements, largely in reference to intermittent military tensions with India. North Korea has publicly pledged to refrain from a preemptive nuclear strike, while threatening retaliation up to and including WMD against conventional aggression. Israel has not declared a NFU policy and it maintains the stance of nuclear ambiguity, but has said it would not be the first country to "introduce" nuclear weapons into the Middle East.