You might look at the last section of the act. No military action is authorized without approval of the Congress. By the way Congress did give approval after being told that there were hundreds of WMD's and a possibility that we would be attacked at any time if we didn't act quickly. Parsing words is not a defense in protecting the bad judgement that was made. Hind sight is always better than foresight, but the intelligence gaffes that were made, intentionally or otherwise, have wasted a lot of lives and resources.
When and if democracy and peace in Iraq are established, then an argument can be made that the whole experience was worthwhile. Unfortunately, it does not look positive with Kurds pulling for autonomy and the Shiite clergy calling for an election allowing their followers to have a referendum making their majority the rulers and religious leaders of Iraq.