I think the justification to most libs for dismissing the domino theory is that communism didn’t ultimately show up on our doorstep, which was originally part of the concern. It did sweep through southeast Asia, however, killing 3 or 4 million after we fled Vietnam, which the mainstream media promptly ignored. See any similarities between that and what the libs want for Iraq?
We didn't flee Vietnam. We left in an orderly manner in 1972 after defeating the Viet Cong and NVA and forcing them to sign favorable peace accords.
Don't confuse film clips of evacuating our embassy in Saigon three years late as "we fled".
We won that war, pure and simple, and left. Later the Democrats refused to fund an enforcement of the peace accords and the communists were allowed to overrun much of S.E. Asia.