The US was viciously attacked on 9/11/2001 by terrorists based in Afghanistan, who had the backing and protection of the Taliban government. I did NOT support the US invasion of Iraq because Iraq had nothing to do with 9/11, and Bush lied to us about the "imminent threat" posed by Iraq's fictitious WMD.
But I did support our counter-attack on Afghanistan as a legitimate exercise of a nation's right of self defense. If our so-called allies aren't with us when we are attacked, then we Americans will know where to stand if they ever call for our help in the future.