So Romney remains front-runner, Santorum's surge is stayed, and the race remains in precarious equilibrium. Next week, it's Super Tuesday, which could see any number of outcomes, including the return of Gingrich as a significant player - he hopes to do well in the south. Alternatively, if Gingrich does badly, he might drop out, and leave Santorum as the only remotely viable alternative to Romney, which would be bad news for the latter. I suspect Romney will continue to do Just Well Enough, which means this race will drag on into the summer.
A long race ended up being good for Obama in 2008. It toughened him up as a candidate, flushed out his vulnerabilities (Reverend Wright etc), and strengthened his profile and organisation in battleground states. But I'm doubtful that the same applies to Romney. The longer this goes on, the weaker he looks. He's not David taking on Goliath, as Obama was; he's trying to overcome a guy who appears to believe that a college education is for snobs, a guy whose most famous policy is lunar colonisation, and...Ron Paul. The more difficult Romney makes this look, the more diminished he becomes, and the more extreme too, in the eyes of general election voters (Obama and Clinton weren't really dragging each other to the left). He is also liable to make more of those priceless bloopers.
Meanwhile, Obama is pulling way ahead of Romney in head-to-head polls, and even beats a "generic Republican", which indicates that the prize of the GOP nomination is losing its value.