The biggest thing Mitt Romney has going for him is his "electability." Now that may be going out the window.

Until now, Romney was thought to be the GOP candidate that had the best chance against Barack Obama in the general election. A new survey from Public Policy Polling finds that Romney trails Obama in a hypothetical matchup by 7 points (49-42%), while Rick Santorum only trails by 5 points (49-44%). Even Ron Paul is putting up similar numbers to Romney, trailing Obama by 8 (49-41%).

Santorum's net favorability is 21 points better than Romney's. Santorum's at -7 (39/46), while Romney is at -28 (29/57). That's mostly because Republicans like Santorum a lot better (+40 at 62/22 to Romney's +2 at 43/41). But Santorum also does a good deal better with independents, coming in at -6 (40/46) to Romney's -23 (32/55). In the head to heads Obama leads Romney by 9 with independents, but has only a 4 point advantage on Santorum with that group.

Why is Obama doing so well? It has a lot to do with this finding: 41% of voters think the economy's getting better to only 31% who think it's getting worse with 27% thinking that it's staying about the same. This is the first time since Obama took office that we've asked a question in this vein on a national poll and found more voters feeling optimistic than pessimstic about the way things are heading.