How did “Domino Theory” play into the Vietnam War?

The domino theory was the basis for the United States strategy of containment, and the reason for entering the Vietnam War. ... The domino theory basically stated if one new countrywent communist in Asia then it would begin a chain reaction that would cause several more Southeast Asian countries becoming communist.

Explanation: hope this helps. It has a little information that I learned about it.

in which two ways were the northeast woodland indians and the southeast indians similar? both collaborated to form the iroquois confederacy. both cultivated the crops of corn, beans, and squash. both lived in rich environments of swamps and rivers. both lived in tree-bark dwellings called wigwams. both expected men to hunt, while women farmed.