It's true--Congress could not--legally-- let W use his "judgment". But it did--and as you say, thereby abdicated its responsibility. Are we surprised?

And the obvious reason is the success of the propaganda campaign to convince the US public that Saddam, being linked to al-Queda, and hence to 9-11, was a clear danger to the US and had to be "taken out"--as a ( dwindling) number of Bush apologists still believe.