The domino theory was

Answer: was a theory prominent from the 1950s to the 1980s that posited that if one country in a region came under the influence of communism, then the surrounding countries would follow in a domino effect.[1] The domino theory was used by successive United States administrations during the Cold War to justify the need for American intervention around the world.

Answer: domino theory was used by successive United States administrations during the Cold War to justify the need for American intervention around the world.