True...but one has to consider the possibility that Iraq may substantially improve within a year.
Or (more likely IMHO) that American involvement in Iraq will decrease substantially by Nov. '08, and so Americans will no longer care that much about what happens in Iraq. Bush could end up withdrawing a significant number of troops by then. In fact, he might have to, if Murtha succeeds in attaching conditions to the war funding that Bush won't accept. What happens then?
I just think way too many people on this forum are reading too much into the political trends of the last year, assuming that everything is going to continue in that direction in a straight line. We have no idea what's going to happen a year and a half from now. You can't predict a presidential election a year and a half in advance. That's not to say that every candidate has an equal shot. There are some who would certainly be favored over others. But saying that you can predict with absolute certainty how every single potential matchup would play out is foolhardy.