What is the domino theory?
The "domino theory" has its origins in the Cold War. It is the belief that nations in Southeast Asia will fall to communism like pushing over the first domino in a row, forcing those next to start a chain reaction of the others falling. This was the United States' political perception of what was going to occur, starting in Korea and Vietnam. This political belief drove policy making in the 1950s. American policy makers were sincere in this mentality and all indications pointed toward a spreading of communism across this region.