Nuclear weapons of the United States

Nuclear weapons of the United States
source
Country	United States
Program start	1939
First test	Trinity (July 16, 1945)
First fusion	Ivy Mike (November 1, 1952)
Last test	Divider (September 23, 1992)
Largest yield	15 Mt (Castle Bravo)
Total tests	1,054 detonations
Current stockpile	~3,750 warheads (2024 est.)
Max stockpile	31,255 warheads (1967)
Current strategy	Nuclear triad, Flexible response
Delivery methods	ICBMs, SLBMs, Bombers
Treaties	PTBT, SALT I, START I, New START

Nuclear weapons of the United States. The United States was the first country to develop nuclear weapons and is the only nation to have used them in warfare, with the atomic bombings of Hiroshima and Nagasaki in World War II. Since 1945, it has constructed a vast and technologically advanced arsenal, forming the cornerstone of its national security strategy through the principle of deterrence. The American nuclear enterprise is managed by a complex apparatus involving the Department of Defense, the National Nuclear Security Administration, and the U.S. Strategic Command.

History

The American nuclear program originated with the Manhattan Project, a secret World War II effort initiated by a letter from Albert Einstein to President Franklin D. Roosevelt. Under the direction of General Leslie Groves and scientific lead J. Robert Oppenheimer, the project achieved the first nuclear detonation, Trinity, in July 1945. The subsequent bombings of Hiroshima and Nagasaki with weapons named Little Boy and Fat Man precipitated Japan's surrender. The post-war monopoly was broken by the Soviet atomic bomb project in 1949, igniting the Cold War arms race and leading to the development of the more powerful thermonuclear weapon.

Development and deployment

Weapon development is overseen by the National Nuclear Security Administration and its national laboratories, including Los Alamos National Laboratory and Lawrence Livermore National Laboratory. The current arsenal is deployed via the strategic nuclear triad: land-based Minuteman III ICBMs under the Air Force Global Strike Command; Trident II SLBMs aboard Ohio-class ballistic missile submarines operated by the United States Navy; and air-launched weapons carried by strategic bombers like the B-52 Stratofortress and B-2 Spirit under the Air Combat Command. Tactical nuclear weapons, such as the B61 nuclear bomb, remain in the stockpile for deployment by allied NATO aircraft.

Stockpile and arsenal characteristics

The active stockpile consists of approximately 3,750 nuclear warheads, with several thousand more retired weapons awaiting dismantlement. This represents a significant reduction from the Cold War peak of over 31,000 warheads in 1967. Modern warheads are characterized by high reliability, safety features like Permissive Action Links (PALs), and variable yield options. The stockpile is maintained without explosive testing through the Science Based Stockpile Stewardship program, which relies on advanced supercomputing at facilities like the National Ignition Facility and subcritical experiments at the Nevada National Security Site.

Command and control

The authority to order the use of nuclear weapons rests solely with the President of the United States, who is accompanied at all times by a military aide carrying the Nuclear football. The president's orders are authenticated and transmitted through the secure networks of the National Military Command Center. Execution authority flows to the United States Strategic Command commander and then to forces in the field. A key component of this system is the E-4B National Airborne Operations Center (NAOC), a survivable command post, while continuity of government is ensured by facilities like Cheyenne Mountain Complex.

Testing

The United States conducted 1,054 nuclear tests between 1945 and 1992, primarily at the Nevada Test Site and the Pacific Proving Grounds. Notable tests include the first hydrogen device, Ivy Mike, in 1952; the largest U.S. test, Castle Bravo, in 1954; and the Plumbbob series. Underground testing continued after the ratification of the Partial Nuclear Test Ban Treaty in 1963. All explosive testing ceased in 1992, leading to the current moratorium, though the nation has not ratified the Comprehensive Nuclear-Test-Ban Treaty.

Policy and doctrine

U.S. nuclear policy is articulated in documents like the Nuclear Posture Review and has historically included strategies such as Massive retaliation and Flexible response. The current doctrine maintains a policy of deliberate ambiguity but emphasizes that the fundamental role of nuclear weapons is to deter nuclear attack on the United States and its allies. The United States is a signatory to key arms control agreements, including the Non-Proliferation Treaty (NPT), and the New START treaty with Russia, which limits deployed strategic warheads and launchers. Extended deterrence commitments to allies like Japan and South Korea under its "Nuclear umbrella" remain a central pillar of its security strategy.

Category:Nuclear weapons of the United States Category:Nuclear weapons by country