Arms Control and Treaties on the Brink Existing norms and treaties governing the GROWING CHANCE OF NUCLEAR use of arms and conduct of war are increas- PROLIFERATION OR EVEN ingly contested, and new understandings are NUCLEAR USE lagging behind technological innovations. Repeated and unpunished violations of rules and norms on nonviolability of borders, assas- Nuclear proliferation and potentially nuclear use are sination, and use of certain prohibited weap- more likely in this competitive geopolitical environ- ons, like chemical weapons, are shifting actors’ ment. Advances in technology and diversification of de- livery systems, arms control uncertainties, and spread cost-bene昀椀t analysis in favor of their use. Renewed competition, accusations of cheating, of knowledge and skills related to nuclear technology and the suspension or non-renewal of several add to the higher risk. major agreements are likely to weaken stra- Countries that have declared their nuclear weapons tegic arms control structures and undermine are adding to or upgrading their arsenals; China and nonproliferation. Russia are investing in new delivery vehicles includ- Reaching agreement on new treaties and ing missiles, submarines, bombers, and hypersonic norms for certain weapons most likely will be weapons. These states are likely to continue to field increasingly accurate, lower yield nuclear weapons on more di昀케cult for these reasons and because of the increasing number of actors possessing platforms intended for battlefield use, which could en- these weapons. Weapons considered to have courage states to consider nuclear use in more instanc- strategic impact probably will no longer be es with doctrines that differentiate between large-scale nuclear exchanges and “limited use” scenarios. con昀椀ned to nuclear weapons as conventional weapon capabilities improve and new capa- Perceived external security threats are increasing in bilities, such as long-range precision strike many regions, particularly the Middle East and Asia, that could put at risk national leadership, o昀昀er which is a key factor in states’ decision to develop powerful e昀昀ects. Countries may struggle to nuclear weapons, according to academic research. reach agreement on limiting the disruptive or Growing questions about security guarantees, extend- security aspects of AI and other technology ed deterrence, and heightened regional pressures because of de昀椀nitional di昀昀erences, dual-use could lead some advanced economies to acquire or commercial applications, and reliance on build their own programs. commercial and often international entities to develop new systems. Incentives for such rules and enforcement mechanisms could emerge over time, especially if crises unfold that show- case the big risks and costs of unrestrained arms development. 106 GLOBAL TRENDS 2040