Was the Iraq war the last straw for the Pentagon to justify its budget?

I am really searching for clues here. Powell tried to pander such outright, blatant lies to the UN and public to get us into war with Iraq, when Afhganistan didn't seem to go well (Dec, 2002) The US public, whipped into a war frenzy by a marketing strategy from one of the top California Marketing Firms was 90% behind Bush on 20 March 2003, going into an illegal war (illegal by the constitution). It wasn't oil (insignificant amounts), there wheren't any weapons, not even an army to speak of. Saddam was 110% contained. So, waht was it now? I think, it was the military industry being on their last leg, after 1989 and the end of the cold war, took all their business away. I just can't fathom another logical reason.