Introduction: Asia-Pacific perspectives on no-first use of nuclear weapons

On 22 January 2021, the first legally binding international agreement to comprehensively prohibit nuclear weapons entered into force. The agreement, known as the Treaty on the Prohibition of Nuclear Weapons (TPNW, or “Ban Treaty”) is an important step on the long road to the elimination of nuclear weapons, an expression of solidarity toward that goal. But the Treaty has been roundly rejected by the world’s nuclear-armed states, which claim it will never become part of customary international law due to their persistent objector status, and which continue to value nuclear weapons as security providers in a world of changing power dynamics and strategic uncertainties. This rejection severely limits the Treaty’s impact: regardless of the Treaty’s other strengths and weaknesses, for as long as the nuclear weapons possessors and their nuclear-dependent allies refuse to accept its prohibitions, it cannot play a practical role in taking disarmament forward. This paralysis, combined with stalled disarmament progress in the wider nuclear nonproliferation regime, has major implications for global security. The dangers of nuclear use, including through a conventional conflict escalating into a nuclear war, are real and growing. Questions over the impact of rising great power tensions and shifting alliances, nuclear modernization programmes, the collapse of arms control agreements, the deployment of new military technologies (including “exotic” dualcapable systems), and the introduction of new domains of warfare (including space and cyber space), have led many strategic experts to reassess long held assumptions about the perceived stabilizing effects of nuclear deterrence. Many scholars and practitioners do not regard the total elimination of nuclear weapons as feasible or even desirable under these conditions and are searching for ways to both reduce the risks of deterrence breakdown and keep disarmament alive. This search is global in scope, impacting not only the world’s nine nuclear-armed states (in order of arsenal size: Russia, the US, China, France, the UK, Pakistan, India, Israel, and North Korea), but also their allies, adversaries, neighbors, and indeed the entire world in the very real sense that a major nuclear war could have catastrophic global consequences. The pragmatic response of significant sections of the international community – including supporters and opponents of the TPNW – has been to revisit the role “no-first use” (NFU) can play in reducing the chances nuclear weapons will be used and in creating conditions that are more conducive to nuclear disarmament. The prospect of resumed US leadership on this issue (US President Joe Biden is known to be sympathetic) has helped spur the launch of an international NFU campaign, bringing together legislators, diplomats, NGOs, academics, and civil society in a new global movement. So, what exactly does NFU entail and what does it promise? Variously referred to as NFU “policies,” “pledges,” “doctrines,” “commitments,” and “strategies” the concept of NFU has multiple dimensions. If implemented comprehensively, NFU policies could reduce threat perceptions and the incentives to conduct a nuclear first strike, build trust and confidence, dilute arms racing dynamics, and improve the prospects for reviving disarmament momentum. This enticing list of security benefits might sound too good to be true, but less so if NFU policies encompass not only declaratory statements (pledges not to be the first to use nuclear weapons, formalized in strategic doctrines), but also concrete actions that back up these declarations. The latter can include nuclear weapons postures that increase