This came as a surprise to me since previous surveys on the subject show Santorum getting the lion's share of Newt supporters if he dropped out.

Gallup's latest survey on the subject shows that Newt supporters would break nearly 50-50 for the other two candidates:

Some conservative Republicans have called for Gingrich to drop out of the race on the assumption that conservative primary voters would then unite behind Santorum as the conservative alternative to the more moderate Romney. But Gallup data indicate that Gingrich voters would not be likely to coalesce behind Santorum, suggesting that factors other than candidate ideology may be attracting voters to Gingrich, Santorum, and Romney.

Gallup can simulate Republican preferences without Gingrich in the race by removing Gingrich votes and reassigning them to his voters' second-choice candidate. The results of this procedure suggest that national GOP preferences would change little if Gingrich dropped out. The reconfigured preferences show Romney getting 40% of the vote and Santorum getting 33%. That seven-percentage-point Romney lead is essentially the same as the six-point (34% to 28%) Romney lead in March 8-15 interviewing with Gingrich support included. (HT: Hot Air)

Allah points out that the latest head to head matchup poll between Romney and Santorum has Mitt ahead 49-44.

Has there been any poll to date showing a surge for Team Sweater Vest if Gingrich drops out? If not, then the best argument for Newt quitting isn't that it would help stop Romney but rather that by staying in he's needlessly impeding the coronation of a candidate who is, unfortunately, inevitable. If you want to beat Obama and think there's no way realistically that Romney, as the leader in delegates, won't be chosen at a brokered convention, then your best option now is to hope that the field clears ASAP so that he can concentrate on the general.

Santorum should win the Missouri Caucuses today while Romney appears to be pulling ahead in Tuesday's Illinois primary. Nothing will be settled on Wednesday, but Romney will likely win another 75-80 delegates and see him inch closer to the 1144 needed for nomination.