Vietnam, the US war, was dought in South Vietnam against local insurgents and regular North Vietnamese forces. It ended with a formal peace treaty, in which the US agreed to withdraw all troops, not send further military aid to the South, return prisoners, remove mines from North Vietnamese harbours and pay, even if called differently, reparations. Vietnam was pretty much a war the US lost, and one that was not exclusively fought against insurgents.
The US won zero strategic goals, Vietnam was reunited by force under the communist North. The US goal was to orevent exactly that. Nice spin so, calling Vietnam a defacto strategic victory for the US.
And Afghanistan, seriously? Before, anti-Talobam forces controlled at least parts of zue country. Nowy the Taliban are in full controll after they over ran Kabul following a hasty retreat of NATO forces from the country, that is as clear cut a loss as it gets. Had the US led coalition left after Bin-Laden was killed, one could have declared a victory. By staying and tuening the whole affaire into a foreign occupation without clearly defined goals, the US-led coalition could only loose. And they did.