In Afghanistan, Iraq, and Vietnam, the enemy was—and, critically, the US forces were not—fighting for their homeland, and the US engaged in political decisions to limit operations because of that (and, in the case of Afghanistan, got distracted and fucked off to start an war of aggression in Iraq in the middle of it).

And still won in Iraq, first against Saddam’s regime, then the post-regime pre-ISIS insurgency, and then the later fight against ISIS, so I’m not sure why Iraq is included, absolute immorality of the decision to go to war there and its cost to the war in Afghanistan aside, since those are irrelevant to the discussion here.