He wanted to make sure that his pet project, i.e.: home loans for Mexican illegal aliens, the one made possible by his Partnership for Prosperity Agreement (with Mexico) and New Alliance Task Force and the one that defined his entire domestic economic policy in his first term, lived a long and profitable life.
His backers were depending on it. They probably had trillions in the pipeline that would be lost if the pipeline blew up.
With the way the dems were mis-managing it, Bush knew, via his backers, that it would blow up before the end of his second term.
So, he tried as best he could to wrest control from Congress before it happened.
Again, not to protect the American taxpayer, but to protect the bankers.
Things would be different for everyone right now
if Congress had listened to Bush 5 years ago