Sebastien Roblin
Today the use of nuclear weapons is a near-unthinkable military option of last resort. But back in the 1950s, that norm had yet to be established. The U.S. Army believed then that in the event of war with the Soviet Union, tactical nukes would be landing left and right across the battlefield. It therefore fielded the “Pentomic” division to fight on the anticipated nuclear hellscape. It even gave battalion-level commanders access to short-range nuclear shells, which risked blasting the units that fired them.
The motive behind the Pentomic divisions may have been more political than military. In the 1950s, the Eisenhower administration believed nuclear weapons were so powerful that conventional ground troops would be rendered irrelevant. The doctrine of “massive retaliation” dictated that the United States would respond to any Soviet attack with full-scale nuclear attack. Indeed, Eisenhower even considered going nuclear to prevent Vietnamese and Chinese Communist forces from securing battlefield victories that were hardly direct threats to U.S. national security.Eager to get a bigger cut, the U.S. Army decided it needed to field a force fit for the nuclear age. At the time, U.S. infantry divisions still had the “triangular” force structure used in World War II, with units organized in threes: three companies in a battalion, three battalions in a regiment, three regiments in a division, and so forth. The battalions in each regiment were supposed to stick close together for tactical, logistical and communications support. However, military theorists worried that large regiments would be make ideal targets for nuclear attacks. To their thinking, numerous smaller, independent units would be more survivable
http://nationalinterest.org/blog/the-mind-blowing-way-america-planned-fight-nuclear-war-19576
