The U.S. military trained special operations personnel to parachute with a Special Atomic Demolition Munition (SADM), or a “backpack nuke,” as part of their arsenal during the Cold War. This practice was part of a strategy to diversify nuclear capabilities by creating smaller, tactical nuclear weapons. These portable nuclear weapons were designed for use in ground operations and to block or deny enemy forces. Despite the inherent risks and ethical issues, this aspect of military history illustrates the lengths the military was willing to go to maintain an advantage during geopolitical tensions. 

Key Points: 

1. The Special Atomic Demolition Munition (SADM) was a small, man-portable nuclear weapon developed by the U.S. military during the Cold War. Weighing about 150 pounds, these were also referred to as “backpack nukes.”
2. The SADMs were part of a broader strategy to create smaller, tactical nuclear weapons. This was part of President Dwight D. Eisenhower’s ‘New Look’ policy that envisaged the use of tactical nuclear weapons in possible conflicts.
3. SADMs were used in training exercises where special operations personnel would parachute with the device strapped to them. This was intended to enable operations behind enemy lines in Eastern Europe to obstruct enemy forces by destroying structures, tunnels, mountain passes, and viaducts.
4. The SADM program raised significant ethical and practical issues. The assigned military personnel often viewed the missions as suicide operations due to the high-risk nature and potential for self-destruction.
5. SADMs were phased out and officially retired in 1989. Their development and use illustrate the extent to which the military was willing to go during the Cold War to maintain an advantage.

Source: https://www.thedrive.com/the-war-zone/special-forces-parachuted-with-nukes-strapped-to-them-during-the-cold-war