Also, the campaign stayed mostly positive. It removed Edwards from the running, and he would have been potential trouble. The long primary in '08 amounted to two democrats talking each other up, and then coming out working together, with the added bonus of Obama demonstrating that he knew a bit about something by managing a good campaign. It was generally an excuse to campaign earlier.
The republicans really are doing Obama's work here for him. The spotlight is off him, and we're seeing each candidate pegged by the other ones into nice, effective negative images. Romney as an uncaring plutocrat who will say anything to get elected, Santorum as a lunatic, and Newt as an evil warlock.
At this point I don't think anyone can see a unified ticket emerging out of the republicans, like the dems did in '08.
If Romney wins the nomination, can you see Newt in his cabinet? Or even Santorum? Ron Paul is obviously out. Who's he going to draw on to rally the base? Bachmann is the only one with the 'star power' to really get some attention, but they're not going to really do a Palin 2.0.
Huntsman and Perry seem like the most likely people for Romney to draw on, but they're not going to do much to make this look like a united front from the republicans.
