7. The US Invasion of Cuba, Oplan 316
During the 1962 Cuban Missile Crisis, President Kennedy’s Joint Chiefs of Staff unanimously agreed that a full-scale invasion was necessary to remove Soviet missiles from the island. They presented JFK with two versions: Oplan 316 for a full invasion, and Oplan 312 for aerial strikes to take out the missiles, followed by an invasion if necessary. The hawks, led by Air Force general Curtis LeMay, preferred Oplan 316, as they contended that there was no guarantee that air strikes alone would take out all the missiles.
Planners expected 18,500 US casualties in the first ten days of the invasion, assuming no nuclear explosions. However, unbeknownst to planners, Soviet forces in Cuba had tactical nuclear weapons, and Soviet leader Nikita Khrushchev had preauthorized their commander to use them at his discretion. If the Soviets used nukes in Cuba, the US intended an overwhelming nuclear response. Things could easily have escalated from there to a full blown nuclear exchange that would have devastated the planet. Luckily, President Kennedy resisted the pressure from his military advisers, and relying on diplomacy, back channels, and blockade, successfully diffused the crisis without triggering WWIII.