Nate Silver notes via Twitter that his compilation of past primary polls shows that pollster error in Alabama and Mississippi "has been about 50% higher than in other states." Also, as blogger Harry Enten points out, three of the final four polls on the Alabama Republican primary in 2008 showed Sen. John McCain (R-Ariz.) leading former Arkansas Gov. Mike Huckabee — two polls showed McCain leading by fairly wide margins. Yet Huckabee defeated McCain, 41 to 37 percent.
Given the close and inconsistent findings of the final polls in Alabama and Mississippi and the poor track record of past horserace polling there, the potential for a Tuesday night surprise is significant.
Despite the close numbers, Philip Klein doubts Romney will be able to pull off wins in either Mississippi or Alabama:
[W]hen there's a critical mass of evangelical voters, Romney loses. To add some numbers to back up this perception, I went back and analyzed data from the 14 exit and entrance polls that have been conducted over the course of the current presidential race. In the nine of those states that Romney won, evangelical voters comprised an average of 33 percent of the electorate. In the five that he lost, the evangelical vote averaged 66 percent of the electorate. In the 2008 primaries, evangelicals made up 77 percent of the vote in Alabama and 69 percent of the vote in Mississippi. And by the time the Mississippi primary had rolled around last time, Mike Huckabee had already dropped out of the race and John McCain had effectively clinched the nomination, so the evangelical turnout will likely be even higher this time around.