Sure they had such. Well, Iraq certainly did.
We invaded. The "alliance" was a creature we created for our own purpose.
You can't impose a democracy on an invaded people; they get cranky about the invasion and will call anyone who cooperates with the invader a quisling, and justifiably so. They aren't angry because they are illiterate. They are angry because they are living in an occupied country. They have an excellent grasp of current events.
If the US had been invaded by the Taliban because Canada, Mexico and Grenada said it was fine by them, Americans would not cooperate either. People in foreign cultures are no less proud and no more willing to be conquered than we are. The US went insane because 40-odd people scattered around the world (not Afghanistan - they were almost all Saudi) set up 4 plane attacks (they couldn't get manpower to crash the planned 12) and killed 3000 Americans on our home soil. Can you imagine what the US response would be if the Taliban bombed us, conquered us, and tried to install a Muslim government and sneered at our ignorance when we refused?
The Taliban rose to power because the mountain tribal thugs we elevated to power after we used them to fight off the Soviet invaders (who were worried themselves of fundamentalist revolutionaries on their border) were such murderous raping hillbillies that the Taliban was welcomed as a less oppressive solution.
The Taliban never attacked us - they weren't suicidal. Some of the people in the loose thing called the Taliban apparently had granted Al Qaida a place to train fighters - but that wasn't ALL the Taliban, just as the Michigan Militia ain't the United States of America. We bombed the country because they wouldn't give up the AQ boys without proof of guilt - somewhat reasonable, granted their culture and common sense. Bush said no proof - give over or die. They chose pride and we blew them up. AQ - all forty of them - mostly got away for awhile, because we were chasing oil in Iraq, but the people of Afghanistan - and Iraq - were annihilated by our blind rage and need to lash out at ANYthing. Thing is, we blew any goals we had - the bad guy got away, and turned the damned planet against us.
I don't see how it was justified. AQ wasn't the Taliban. We conflated, and still conflate, all Muslims who defy us as AQ. We blew up a country - two countries - that had nothing to do with the attack against the US. This is the cognitive dissonance that Americans won't confront, because then we wouldn't be good guys. We needed their cooperation, and instead turned them into enemies. and once again, the bad guy got clean away.