As the subject of "winning in Iraq" is debated, reference is made to how the U.S. lost in Vietnam by leaving too soon. That claim is used as an argument for staying longer in Iraq. The situations are different of course, but shouldn't one consider what did happen after the U.S. lost and left Vietnam?
First, there was eventual control over all of Vietnam by the communist north. Second, no dominoes fell. Communism did not spread across southeast Asia, as had been predicted. Third, there was no further loss of American lives or dollars.
There is still communism in Vietnam and we have diplomatic, cultural and business relations with that country, which is now visited by American presidents past and present. There are heartfelt reconciliatory visits by former soldiers.
In sum, it is hard to say the U.S. lost in Vietnam as we view that war in the prism of history. To use it as a justification for continuing the war in Iraq does not seem to withstand factual scrutiny.
"Losing" in Iraq will certainly save American lives and wealth. We can't know the rest of the story. If Vietnam had huge oil reserves, would we have ever left?