The sovereignty is not for Iraqis. it's a political ploy for Bush. The Insurgents are increasingly becoming (if they weren't already) the Iraqi people who find the common "enemy" in American troops.
Bush has made promises before that have gone unfunded. His nation building has no real monetary committment behind it. If the congress doesn't fund it, then he can blame them and once again absolve his responsibility for his actions.
The oil money was never intended for Iraq.
Doesn't this sound like a replay of Vietnam? If the US were to pull the troops out of Iraq and declare it the winner of the war, it would be easy for America to bring in all the corporations it wanted. Isn't that pretty much what happened in Vietnam?