To say the economy began to crumble under Bush does not establish blame on Bush. Sure, he received blame, but wherein was such blame deserved and wherein was it not deserved is the question.
Fanny and Freddie? The Bush people saw that one coming. They tried to warn, but were rebuffed by the Dems in Congess. Barney Frank and Maxine Waters et al ridiculed and stonewalled the warning and it was people like them that held Congressional power.
I was very tuned in to the economy when it became obvious that Obama actually might win the election. If you look at when it began to totally tank bigtime, it was when people who move and shake the economy - from Wall Street to Main Street - realized this and were struck with a sick fear of what this leftist would do in office to harm the economy.
They reacted accordingly, and their fears of an Obama Administration were dead on as subsequent events have proven.
Bush gets blame for falling for the "sky-is-falling" scheme leading to the 700 billion(?) bail-out under his watch. Many have stated it would have been better to just let the chips fall and fail to prop up institutions that played and lost. I agree. We went MONTHS before they even started spending that money, so obviously the insistence at the time that it happen before a particular day (Friday?) was clear alarmism.