Note: Click graphic to enlarge.

Mitt Romney’s polling has remained relatively steady since his decisive Florida victory. However, we may not have yet seen the full impact in the polls of Rick Santorum’s sweep of the non-binding primaries. His performance has been inching upward, but Santorum has not experienced the shock of sudden popularity that the other anyone but Romney (ABR) candidates have. Looking at the trend chart to the left, you can see back to the first of September when Rick Perry was at his peak of national popularity. Then there was the momentary rise of Herman Cain, followed by the first, and more significant, Newt Gingrich surge. Rick Santorum’s initial national rise came out of his win in Iowa, though he never reached the levels of popularity gained by his three predecessors.

Corresponding with Santorum’s slow rise is Gingrich’s second demise. Once again, there may be a split in voters between the former two candidates that continues to favor Romney, especially if Santorum does not experience the sharp rise in popularity the other ABR candidates have. Assuming either Gingrich or Santorum were to drop out today, their combined PD Composite score is only 3.6 percent ahead of Romney. Therefore, to overtake Romney, the remaining candidate would have to garner nearly all of the the other candidate’s support, hoping none moves to Romney.