
The conventional wisdom is that Democrats benefit when the conversation turns to the economy. You might think that the opposition of conservative Republican House members to the bailout could provide a boost to McCain's campaign insofar as it distances him from Bush, who is pushing the plan. But to make that work, I think McCain would have to be (far) more comfortable discussing economic issues than he is. So I think McCain still loses on this.
Buck Naked Politics has a good summary.