Philip Klein is skeptical:
[L]et’s not get too carried away. What we’ve learned in the primaries up until this point is that each contest tends to be an independent event, with the concept of momentum not meaning as much as it usually does. This was the case when Santorum won Iowa only to fade for several weeks; when Romney won New Hampshire and then fizzled as Newt Gingrich came back from the dead in South Carolina; and when Gingrich was riding high heading into Florida, only to go down in flames. Then Santorum, having disappeared, came back to pull off the hat trick in Minnesota, Missouri and Colorado. There’s a good case to be made that Santorum fought hard on Romney’s home turf, and could win the delegate-rich Super Tuesday states of Georgia, Ohio, Oklahoma and Tennessee.
For me, the key question is class and religion. If Romney cannot win a Southern state with Christianist voters or keeps losing the white working and lower middle class, he's a very weak nominee. Which means he will have to pick a red-blooded red-stater as a veep. I think Rubio's Mormon period effectively rules him out as an option. My suggestion? Huckabee as veep. He balances every Romney weakness.
The Dish 