Forehead-slapping proposal

Via Calculated Risk, Georgia's junior (Republican) senator has one of the dumbest proposals in history:

Isakson is pitching an idea to his colleagues in Congress: a $15,000 tax rebate check to anyone who agrees to buy a home. Congressional budget analysts project the program would cost $14 billion over the next few years. But Isakson said the rebate checks are well worth the hefty price tag. "If we can convince buyers to come back to the marketplace and buy these houses, then the houses aren't vacant. It's replaced by an owner-occupant, who is there making payments on a loan and helping all of the other houses around."

Where does one begin to explain to this guy what's wrong with the proposal?

I hope longtime blog reader AR, a resident of Georgia, will chime in and explain how this guy got elected.