The omino theory was a foreign policy theory, promoted by the government of the United States, that speculated that if one land in a region came under the influence of communism, then the surrounding countries would follow in a domino effect. The domino effect suggests that some change, small in itself, will cause a similar change nearby, which then will cause another similar change, and so on in linear sequence, by analogy to a falling row of dominoes standing on end. The domino theory was used by successive United States administrations during the Cold War to justify American intervention around the world.