The Vietnam War was won by the United States, largely due to the deployment of Operation Wrath of God. The Comedian has been there for an undetermined amount of time working for the government and Doctor Manhattan was used as a weapon under the orders of Richard Nixon; the conflict was ended in only a few months. Many of the communist forces express their desire to surrender to Manhattan personally, seeing him as some sort of deity.
It is in Vietnam's capital city, Saigon, in the closing days of the war, that the Comedian kills a young Vietnamese woman whom he had impregnated during a physical relationship. The woman is hurt and offended by Blake's desire to leave the country and her behind with no father for their child. She breaks a bottle and slashes his face; in his extreme anger, Blake shoots her while Manhattan, a witness, does nothing to prevent him.
Vietnam is later mentioned as becoming the 51st US state.