If Mr. Gingrich drops out, where does his support go? … [T]here’s not that much support to go around — one of Mr. Gingrich’s biggest problems, in fact, was that he lacked a natural constituency within the party, and wasn’t entirely trusted either by the Republican establishment or by insurgent voters who take their cues from the Tea Party. …

Does this mean Rick Perry is likely to run? … If Mr. Perry were to run … I’d expect him to run a traditional campaign — which means that I’d expect him to throw his hat in the ring sooner rather than later. Of course, Mr. Gingrich’s staffers could have decided to leave for any number of other reasons apart from going to work for Mr. Perry — but the theory that Mr. Gingrch’s loss could be Mr. Perry’s gain passes the smell test.

Why is Mr. Gingrich’s campaign going so badly? One reason may be that he hasn’t run in a competitive race since 1990, when he eked out a a victory by less than a full percentage point over the Democrat David Worley to maintain his seat in Congress. (After that, Mr. Gingrich benefited from redistricting and began to win by blowout margins.) And that was a race for the House of Representatives, not for the presidency.