we went in there to root out the the Taliban government and the Al-Qaeda movement they were sponsoring, following the 9/11 attacks. I don't have any problem with that; further attacks needed to be nipped in the bud.
I didn't think we'd succeed, but I was very nearly wrong. We actually came quite close. But then Bush took his eye off the ball and decided to invade Iraq as well, and Blair of course went along with this. We had no particular business being in Iraq, and it meant our efforts were divided.
Now we've left the Iraqis to it, possibly a bit better placed than they were before (and perhaps with a government that might sell us cheaper oil, which we all want, don't we?) But in Afghanistan we're going nowhere. Should we pull out, leave the Taliban to regroup and sponsor more 9/11-style attacks? Or keep at it? People are likely to die either way. If we stay, they'll be soldiers. If we pull out, they're more likely to be innocent civilians.