From what I have seen lately, even with an approval rating of 40% Obama is still beating the GOP in the polls. The fact that santorum is doing so well does not bode well for the GOP. I think it will be 4 more years of Obama no matter what happens with the economy or gas.
Santorum really
isn't doing that well. He's FAR behind in the delegate counts (150 to Romney's 396), and I don't see him catching up. There just aren't many more deep dark south states left to vote ... and it's not like he's going to do well in California or Utah. He might split Texas with Romney. Generally, except for one state (MN), Santorum's primary victories have been marginal and have awarded Romney almost as many delegates as he got. Pretending it's a tight race makes for good ratings.
Santorum is, of course, emblematic of everything that's wrong with a GOP faction that would rather lose screeching stylish derp than win with a moderate. After 2008, I thought the Republican party would realize that the Palin-right freepers were a big part of McCain's failure (plenty of other reasons too) and I hoped that the party would decide it hated losing more than it liked pandering to the religious right.
I think there's a good chance Obama will be re-elected if Romney is the nominee.
I also think it's waaaaaay early to make emphatic predictions about the general election. Primaries are very fluid and voters have short memories (Cain? Perry? Who?). All the Republican faithful who are getting riled up by Gingrich and Santorum against that "Massachussets liberal" will also be easy to rile up against that black Kenyan moooslim in November.
Neither Obama nor the R nominee have started nationally campaigning. All the R candidates take swipes at Obama here and there, but their hearts aren't in it yet. A lot can and will happen in the next 7 months.
I wouldn't put money on or against Obama today, but I'd leap at a chance to bet against Santorum.