We will stay because a just nation cannot leave to the cruelties of its enemies a people who have staked their lives and independence on America's solemn pledge—a pledge which has grown through the commitments of three American Presidents. We will stay because in Asia and around the world are countries whose independence rests, in large measure, on confidence in America's word and in America's protection. To yield to force in Vietnam would weaken that confidence, would undermine the independence of many lands, and would whet the appetite of aggression. We would have to fight in one land, and then we would have to fight in another—or abandon much of Asia to the domination of Communists. And we do not intend to abandon Asia to conquest.

State of the Union Address (1966)