These results are based on Gallup Daily tracking interviews conducted March 8-15 with more than 1,900 Republican registered voters, including a sample of 290 Gingrich supporters. 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...