The US isn't the only nation there, Australia and alot of other nations have been there since day one also. We have also suffered terrorist attacks because of it.

There are a number of ways that it could have been handled, I'm not sure how much of it is legal in today's world of law for wars but cutting off Kabul from the rest of the nation and setting up a permanent fixture to support the Afghani people could have been one.

But then the risk of establishing another Hamas and Isreal situation also occurs.

I think the devil in the detail is that the Taliban had 75,000 troops while the US and allies trained up 300,000 Afghani military. All of which fled or put down arms. So clearly alot don't want the US there. But what of the millions trying to flee?

I personally don't think this is over and splinter cells are already starting to form.