Lets be real. When Truman got into Korea and Johnson got into Vietnam they intended a negotiated settlement and the end game in Afghanistan looks pretty much the same.
We fight wars under international law and United Nations rules with total World War II style victory out of the question.
The military force in Afghanistan right now the USA is part of is called the “International Security and Assistance Force” under United Nations authorization.
Let's be real. Korea and Vietnam were both divided with the commies. In the former case, the peninsula remains divided. In the latter, the Demwits in Congress just pulled the plug and our former client and ally was overrun. Our first Afghanistan intervention started under Carter and continued under Reagan, and contributed the downfall of the USSR, without any US troop commitment. Our second intervention was in response to bin Laden's mass-murders on US soil -- except for nitwit "truthers" who blame it on the Jews or whomever really killed OJ's ex-wife since OJ didn't do it.