Answer:
The domino theory was a theory raised extensively in the 1960s. The theory posited that if one country in a region came under the influence of communism, then the surrounding countries would come under communism.
Explanation:
The Domino effect raised in foreign policy during the Presidency of Kennedy and Johnson to support America's military involvement in the Vietnam War.
Historically, the domino theory considered a weak model for foreign relations. The United States crashed repeatedly in the Third World by removing governments to limit the influence of communism. The domino theory gave reason for the Vietnam War, which cost the United States almost 50,000 lives.