If this split continues — Romney in the West and Northeast, Gingrich in the South, and Santorum in the Midwest — we could easily find ourselves in a scenario where no candidate crosses the 1,144-delegate threshold by the time voting ends. Consider this: Right now, Romney barely has a majority of the delegates. If Gingrich successfully contests the winner-takes-all allocation in the Florida primary (based on the RNC’s rule against such a format before April), no one would have a majority of the delegates as of today…

So the viability of a three-way split probably comes down to Ohio, which has a fair number of evangelicals, though not to the degree that Tennessee, Oklahoma and Georgia do. Santorum has some strengths he can draw on in the Buckeye State, as his blue-collar message could play well even among Republicans there. If he wins, it means that we probably do have a deeply divided GOP, with Gingrich taking the anti-Romney vote in the South, and Santorum taking the anti-Romney vote in the Midwest.

The key is that neither Gingrich nor Santorum can begin to do so well that the other drops out. Both must remain effectively regional candidates. If Gingrich’s support collapses in the South, it might leave an opening there for Santorum. We’ve seen some potential evidence of this, as Gingrich’s support in Gallup’s tracking poll is down about seven points since the Florida primary (although it isn’t down in the wake of Santorum’s wins Tuesday night). If that were to occur, we would be back to a two-person race.