You might expect that a candidate who performs tenuously among very conservative voters but pretty well among somewhat conservative voters would remain on a linear trajectory and do quite well indeed among moderates. Mr. Romney, however, has averaged only 24 percent support among moderate Republicans. While this total leads the Republican field, it is not doing as much as it might to help offset Mr. Romney’s disadvantages with the most conservative Republicans. Moreover, the middling total comes despite a lack of competition for the moderate vote, although both Ron Paul and Jon M. Huntsman Jr. are doing considerably better with moderates than they are over all…

What this seems to suggest is that Mr. Romney may have calibrated his ideological pitch a bit too finely. While not having made much headway with the most conservative Republicans, moderates are also somewhat leery of him. Were Mr. Romney polling at 40 or 50 percent among moderates instead, numbers that you might intuitively expect from a candidate who is often critiqued from his right, his base of support against surging candidates like Mr. Gingrich would be more robust. But so far he has posted somewhat underwhelming numbers with this group.

Mr. Romney’s failure to shore up the moderate vote also creates the potential that he might have to fight a two-front war. The key player here would almost undoubtedly be Mr. Huntsman, whose national numbers remain weak but who is now polling at about 10 percent in New Hampshire. If Mr. Huntsman continues to improve on that total, it could cut into Mr. Romney’s margin in the state and perhaps allow a candidate like Mr. Gingrich to beat him there with around 30 percent of the vote.