He absolutely did make it clear we needed to stay in Iraq until it was a stable democracy and that might take a considerable period of time:
http://www.cnn.com/2007/POLITICS/01/10/bush.transcript/
The consequences of failure are clear: Radical Islamic extremists would grow in strength and gain new recruits. They would be in a better position to topple moderate governments, create chaos in the region, and use oil revenues to fund their ambitions. Iran would be emboldened in its pursuit of nuclear weapons. Our enemies would have a safe haven from which to plan and launch attacks on the American people. On September the 11th, 2001, we saw what a refuge for extremists on the other side of the world could bring to the streets of our own cities. For the safety of our people, America must succeed in Iraq.
And, he was right about that. It was moronic for Obama to live Iraq too early. Once we were there, we shouldn't have left and let ISIS takeover much of the country.
The war was a mistake but so was leaving too early.
You are right about that, I think that once we were in we should have stayed. The problem is that a US President cannot set policy beyond his time in office. I guess the lesson should be that if wars cannot be concluded fairly quickly it is probably wise not to start them in the first place.