The Democrats were deciding which historic nominee excited them most. Republicans can't decide who depresses them least.
Asked if they're worried by the extended primary contest between Mitt Romney and Rick Santorum, a lot of Republicans are playing it cool. Said Senator Mitch McConnell, "It's reminiscent of the contest between Obama and Clinton. That didn't seem to have done Democrats any harm in the general election, and I don't think this contest is going to do us any harm either."
But the GOP contest is actually very different from Obama versus Clinton. In 2008, there was no incumbent. Insofar as progressives demanded that a candidate take a position to prove his or her bona fides, it was opposition to the Iraq War, which a majority of Americans had already turned against. On health care, Obama opposed an individual mandate, calculating that he'd benefit from a more centrist position. What else separated the pols? Clinton argued that she had more experience and was better prepared to take a "3 a.m phone call;" Obama retorted that his judgment was superior, as evidenced by his early opposition to the Iraq War. The two also disagreed about the nature of Washington, D.C. Obama argued that fundamentally reforming the system was a prerequisite for the substantive changes he desired, whereas Clinton argued that realism demanded working within the system, and that she'd excel at doing so.