President Lyndon B. Johnson State of the Union Address, Vietnam excerpt
January 4, 1965

Why are we there ?

We are there, first, because a friendly nation has asked us for help against the Communist aggression. Ten years ago our President pledged our help. Three Presidents have supported that pledge. We will not break it now.

Second, our own security is tied to the peace of Asia. Twice in one generation we have had to fight against aggression in the Far East. To ignore aggression now would only increase the danger of a much larger war.