During the Cold War, the United States developed a vast nuclear arsenal with weapons on aircraft, submarines and land-based missiles. These three ways of delivering nuclear weapons became known as the triad, with the Soviet Union was the primary target.
The strategy was to deter an attack on the United States by having enough nuclear weapons that could survive a strike and retaliate.
Former Clinton era Defense Secretary Bill Perry clashes with Jim Miller who served as Under Secretary of Defense for Policy during the Obama administration.
Perry says America does not need the triad of nuclear weapons. He advocates retiring the intercontinental ballistic missiles and not building new long range cruise missiles that can be dropped from aircraft. On the other hand, Miller says these missiles are needed as a hedge in case there is a problem with the submarines.