Nuclear deterrence is the doctrine that underpins the possession and proliferation of nuclear weapons. It does so by making the possession of nuclear armaments more acceptable by ascribing to them the pre-eminent role in preventing aggression from others.  Though nuclear deterrence is presented to the public as an insurance policy against weapons of mass destruction being used, military strategists argue that for adversaries' behaviour to be influenced, a nuclear deterrent must appear credible, which requires policies and operations to demonstrate the capability, conditions and preparedness to use nuclear weapons.  The Acronym Institute works on delegitimizing nuclear deterrence as an essential early step towards preventing proliferation and achieving and maintaining a world free of nuclear weapons. This is carried out in conjunction with reducing the role of nuclear weapons  and linked to our work on humanitarian disarmament, the NPT, security assurances and denuclearising security alliances such as NATO.

Nuclear deterrence doctrines have been used to justify the retention and modernization of current arsenals as well as past build ups. Over time, the nuclear-armed states have crafted a variety of nuclear deterrence doctrines, including: US-Soviet Cold War mutual assured destruction (MAD); NATO's flexible response, last resort and "tailored deterrence", "deterrence by the weak" employed by Pakistan and North Korea, for example, fearful of interference by nations with superior forces; Britain's comfort blanket of "minimum deterrence" and "nuclear insurance" France's "dissuasion" and "defence of vital assets", and a variety of real or questionable "no first use" promises combined with "survivable" second strike capabilities (Soviet Union, China and India). NATO and Russian insistence on keeping first use options and maintaining nuclear weapons on high alert increase the risks of miscalculation, inadvertence or accident.

The Obama administration is rightly applauded for reducing the "fundamental role" of US nuclear weapons to "deter nuclear attack on the United States, our allies, and partners". Nonetheless, the 2010 US Nuclear Posture Review (NPR) retained a "narrow range of contingencies" in which the US would consider using nuclear weapons "in extreme circumstances".   As with current efforts in Britain to move beyond "continuous at sea deterrent" patrols (CASD), such changes may be useful for those seeking to reduce roles, neutralise opposition or lower costs while holding on to some nuclear weapons.  They don't, however, tackle the core problems relating to nuclear deterrence theory and practice, which act as drivers for proliferation and insecurity.

The fundamental change that is needed is the recognition that nuclear weapons are not a useful or reliable component in the mix of diplomatic, political, psychosocial and military tools that contribute to deterrence. Contrary to the impression conveyed by the UK practice of labelling Trident "our deterrent", deterrence is not an attribute of any weapon as such, but a multifaceted relationship between potential adversaries in which varying degrees of threats, reprisals, costs and consequences are communicated with the intention of preventing attacks and dissipating serious threats. Deterrence, like all strategies, sometimes fails. Relying on nuclear weapons makes failure catastrophically more costly than for other security strategies. This may contribute to deterrence via the nuclear taboo, but can also attract suicidal or terrorist attackers willing to turn cities into radioactive wastelands.  Whether or not someone is deterred by particular threats, weapons or information depends on intentions, communication, perceptions of what is at stake and the understanding and decision making of adversaries. Equating nuclear weapons with deterrence and insurance policies sanitizes these weapons of mass destruction, increases their value for proliferators as well as the nine nuclear-armed states, and impedes progress on nuclear disarmament.