Newt Gingrich. Republican voters seem to want in their hearts to vote for Mr. Gingrich — they see him as the strongest leader, the best qualified, and the closest to them on the issues. But they see Mr. Romney as considerably more likely to defeat Barack Obama.

The thing about electability, however, is that nothing makes you look more electable than actually winning an election. Winning Iowa would remove many of the doubts about Mr. Gingrich’s viability and staying power and provide him with a fundraising boost that his campaign badly needs.

Win Iowa, and there is a real possibility that Mr. Gingrich is the Republican nominee. He is a reasonably strong candidate for Florida and South Carolina. His polling has been all over the map in New Hampshire, meanwhile, but one recent survey puts him quite close to Mr. Romney in the state, and New Hampshire has long had a thing for more intellectually-minded candidates (like Paul Tsongas or Mr. Hart) and for curmudgeonly conservatives (like Pat Buchanan).