Doctrine & strategy

Permissive Action Link (PAL)

A security device built into nuclear weapons that prevents unauthorized arming or detonation without the correct code.

PALs were first deployed by the US in 1962 to prevent rogue or stolen weapons from being used. Modern PALs disable the warhead if tampered with. The Soviet Union and Russia use a different system based on centralized release codes.

Related terms

Warhead

The explosive payload of a missile, bomb, or other weapon system; for nuclear weapons, the package containing the fissile or fusion material.

First Strike

A nuclear attack intended to disarm an opponent before they can retaliate, by destroying their nuclear forces, command, and control.

See the full Nuclear Weapons Glossary.