(Sounds like Antigone)

The UN and hard-work rarely are uttered in the same statement, unless there is a negative interjected in between the 2.
A combine nations force, the local Afghani's who were seeking to free themselves of the Taliban's influence.

And now, with the liberation and democratization of Afghanistan, things are looking up. It's a HUGE investment opportunity, and companies are moving in, to exploit a labor base that has often been passed over. Telecommunications companies have a new buyer group, and all in all, I think that business investment will continue.
Unless.....
The Taliban can come back and break the local Afghani forces and the NATO troops posted there. Hopefully the Taliban will be broken, Osama Bin Laden is caught, and peace enters the region. While reality interjects it's pessimistic, I'm feeling good about it.

Now to main question.
The US was justified in removing a regime who harbored acknowledged terrorists and killers. AQ is one of the groups that trained in the area, and had an anti-US mindset. You can't diplomatically solve an issue when

a.They aren't a nation
b.The nation they live in is also anti-American.

We punished those responsible for harboring terrorists and violent malicious men who punished the innocent in Kenya and in their attacks against the United States.