Delegates are handled in a complicated way in Louisiana. Twenty of the state's 46 total delegates are up to be won tonight, and the state portions them out according to percentage of the vote - as long as a candidate meets a 25% barrier.
Dave Weigel explains,
The only candidates who get them are the ones who grab more than 25 percent of the vote. Let's say Rick Santorum gets 40 percent, and Mitt Romney gets 25 percent. That would mean Santorum got eight delegates, Romney got five. The seven remaining delegates would be uncommitted.There's a twist! Say Santorum got 39 percent and Romney got 25 percent. In that case, all 20 delegates would be uncommitted. The total vote for every candidate who crosses the 25 line needs to exceed 65 percent, or no one gets anything to show for it.
According to Fox News exit polling, Santorum looks to sweet almost every demographic in Louisiana tonight. He'll win amongst conservatives, Catholics, Protestants, college graduates, women, gun owners, even moderates.
Exit polls can often be overanalyzed and the media can read too much into them, and the media often reads larger narratives into them. In Louisiana, the narrative fits Romney again: he is winning the over-$100,000 income demographic, the postgraduate-educated demographic and the "somewhat religious" demographic who doesn't attend church very often.
Watch out for other memes that the media likes to harp on. The New York Times claims that turnout "appears light" in Louisiana. The MSM likes to claim that low turnout is a sign that Republicans aren't excited - which might be the case - but wants to convince Americans that low primary excitement means Barack Obama is unbeatable. The MSM did the same in Illinois last week - and turnout there exceeded 2008.