domino theory

American  

noun

1. a theory that if one country is taken over by an expansionist, especially Communist, neighbor, party, or the like, the nearby nations will be taken over one after another.

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domino theory Cultural  

1. The idea that if one key nation in a region fell to control of communists, others would follow like toppling dominoes. The theory was used by many American leaders to justify American intervention in the Vietnam War. (See policy of containment.)

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Etymology

Origin of domino theory

First recorded in 1960–65

Example Sentences

Finally, I stopped believing in the domino theory long ago.

From Washington Post • Dec. 30, 2022

However, Japan was, and President Truman, in keeping with the domino theory, believed a stable non-communist Korea was necessary to protect Japan.

From Textbooks • Dec. 14, 2022

This belief in this domino theory was so strong that the United States broke with its European allies and refused to sign the 1954 Geneva Accords ending the French war.

From New York Times • Jun. 9, 2021

Wells said he and his fellow midshipmen saw the Vietnam War in terms of the domino theory regarding communism in southeast Asia.

From Washington Times • May 20, 2017

Brew said the same thing about the domino theory.

From "Fallen Angels" by Walter Dean Myers