Was this not told?

Highway #1, North of Qui Nhon

I was told the U.S. got involved when after Eisenhower signed the South East Asia Treaty Organization treaty in 1954, giving all of Vietnam free elections in 1956, his advisors said, "if we allow that, the whole country will vote for Ho Chi Min and we don't know where he stands, he might be leaning toward Communism." So he broke the treaty. If this is true, why was this not told in the film?

Bill McCoy
Hopewell, Aliquippa, PA