Saddam was pretty much the only thing holding Iraq together...
I'm not sure he was holding much of anything together. The status quo in Iraq was unsustainable, and presumably would have broken one way or another within ten years, even without a US invasion. Though that's not to say that Saddam wouldn't still be holding onto a lot of territory today. But you could have had a Syria-like civil war, with Saddam as leader of a rump Sunni state, battling against the Shiite and Kurdish regions, or something like that.