For all of Saddam's faults, the US turning left into Iraq in 2003 before the Taliban in Afghanistan were subdued, was, IMO, a huge tactical mistake.
That one should have been a NATO/UN effort. Laughable, I know, but a coalition akin to DS/DS should have been established in an effort to contain him.
The destabilization of Iraq only exacerbated the problems in that area, as evidenced by the rise of ISIL and the subsequent civil war in Syria.
I agree that "nation building" in a 3rd world $h!t hole like Afghanistan is a mistake and history has shown that to be true for all who have tried.
But, we need to keep the pressure on the Taliban to prevent giving them "breathing room" to possibly stage another 9/11.
We also need to extricate ourselves from the Syria quagmire as well...