While I generally agree with your conclusions, every President has to deal with what comes up and what has developed over the past few years. If Bush had a third term, or McCain had won in 2008, there would have still been a very large deficit due to the housing/finance induced depression. That took many years to develop into it’s full-blown form—maybe 20 to 25.
Nevertheless, Dem congresses and Dem presidents make things worse. I don’t believe that McCain would have gone for a union/government employee directed Porkulus bill, although there would have been significant recession induced stimulus. And, I believe McCain (or Bush if he could have been in office) wouldn’t have gone crazy with job killing and energy killing over-regulation.
Yes, any GOP President elected in 2008 would have had a problem to face, but I believe the deficit would not have broached $700 billion, and would be back down below $400 billion now, with unemployment down in the 7% range, with GDP growth in the 2-3% range.
The simple reason is that much of our current economic meltdown is because of the actions taken by the President - not doing anything, or doing it to a much smaller scale, would have allowed the economy to recover naturally, instead of the forced-approach the Obama Administration is attempting.