The '''Domino theory''' was a phrase that became popular during the administration of U.S. President Dwight D. Eisenhower. According to this theory, once nations such as Vietnam fell to communism, other countries of Asia would fall like a row of standing dominos, one after the other, each knocking the next over. | The '''Domino theory''' was a phrase that became popular during the administration of U.S. President Dwight D. Eisenhower. According to this theory, once nations such as Vietnam fell to communism, other countries of Asia would fall like a row of standing dominos, one after the other, each knocking the next over. |