Weapons of Mass Destruction and Nonproliferation

Weapons of mass destruction — nuclear, chemical, biological, and radiological — pose a different order of threat than conventional weapons, and preventing their use or spread has been a central goal of American foreign policy and defense strategy for decades. This category covers how the government identifies these threats, how it plans to deter or respond to them, and how international agreements try to limit their spread in the first place.

Detection and warning come first: before any decision can be made, officials need to know what threats exist and where. A wide network of agencies, laboratories, and intelligence tools works to spot nuclear materials and weapons programs around the world, a process explained in How America Tracks Nuclear Threats.

Deterrence and response shape what happens once a threat is identified. The United States relies on a mix of military readiness, alliances, and declared policy to discourage other countries from ever using such weapons, described in How America Responds to Nuclear Threats, alongside the detailed strategic and civil-defense planning covered in How America Plans for Nuclear War.

Arms control and diplomacy aim to prevent these weapons from spreading before deterrence is ever tested. Treaties that verify and limit weapons stockpiles remain a major tool, as outlined in Arms Control Treaties and Department of Defense Compliance, while regional disputes over weapons programs, such as the long-running standoff with Iran, show how nonproliferation efforts intersect with broader diplomatic relationships, a history traced in U.S.-Iran Relations: From Allies to Enemies.