As of 2025, nine countries are recognized as possessing nuclear weapons: the United States, Russia, the United Kingdom, France, China, India, Pakistan, Israel, and North Korea. The U.S. and Russia hold the vast majority of the world’s nuclear arsenal, together accounting for nearly 90% of an estimated 12,000 total warheads. Both maintain strategic triads consisting of land-based ICBMs, submarine-launched missiles, and strategic bombers, while investing heavily in modernization. The UK and France maintain smaller but sophisticated deterrents centered on submarine-launched ballistic missiles. China is rapidly expanding its nuclear force, adding new silos, submarines, and delivery systems, signaling a shift from its long-standing “minimum deterrence” posture. India and Pakistan, nuclear rivals since the late 1990s, maintain arsenals of roughly 150–200 warheads each, driven by regional tensions and a focus on deterrence stability. Israel retains an undeclared but widely accepted nuclear capability under a policy of “opacity,” while North Korea has continued producing fissile material and developing delivery systems despite international sanctions, now believed to possess dozens of operational warheads. Outside these nine states, Iran remains closely watched for its nuclear potential, though it is not known to have an assembled weapon. The broader trends show global modernization of arsenals, waning arms-control regimes, and technological advances—such as hypersonic weapons and MIRVs—complicating deterrence. Strategic doctrines vary widely, from U.S. high-alert readiness to India’s declared no-first-use and Israel’s ambiguity. The existence of these arsenals underscores enduring global tensions between deterrence and disarmament. Despite decades of treaties and reductions, modernization continues, and new regional threats emerge. The challenge for the international community lies in rebuilding arms-control frameworks, ensuring transparency, and preventing new proliferation, while acknowledging the catastrophic humanitarian and environmental consequences that any nuclear use would bring.