In the 1950s President Eisenhower believed that if one country in Southeast Asia fell to communism then the neighboring countries would become communist as well. This concept was known as the domino t?

The "domino theory," articulated by President Eisenhower in the 1950s, suggested that the spread of communism in one Southeast Asian nation would trigger a chain reaction, leading to the fall of neighboring countries to communism as well. Eisenhower used this theory to justify U.S. intervention in countries like Vietnam, arguing that the loss of any single nation to communism would threaten regional stability and U.S. interests. This belief significantly influenced American foreign policy during the Cold War.