It's possible:
Although Santorum is an easy favorite, Louisiana is unique enough that there should be a degree of uncertainty about the eventual result. French Catholics in Louisiana are culturally southern, but definitionally not evangelical and strongly supported McCain in 2008. We can’t discount the possibility that these voters ultimately support Romney, even if it seems somewhat unlikely.
When I wrote this piece eight days ago, Gingrich had just come off strong performances in Mississippi and Alabama. If the conservative vote is as divided in Louisiana as it was in Mississippi and Alabama, Romney has a real shot. However, Gingrich performed exceptionally poorly in Illinois. If Gingrich falls far beneath 30%, Santorum is likely to benefit and Romney’s narrow opening will probably close.
The Dish 