As you can read here, columnist Kathleen Parker wastes way too much ink in supplying us with the answer. She claims Republicans like New Gingrich because he represents someone who has risen from the proverbial ashes of sin to redemption. Or, in her words:

To many Republican voters, Gingrich is “one of us,” a familiar face, a known quantity. Most important, he has done the single thing that transcends sin. He has confessed and repented. …

Bottom line: Most Americans would rather embrace a man who has fallen and climbed back to his feet than one who has never stubbed his toe on temptation. The successful protagonist is always flawed. In Romney breaking news: He removes the cheese from his pizza but has a weakness for chocolate milk. Mr. Squeaky not only has no skeletons in the closet; he has no closets.

I think I have a better answer. Brace yourselves:

Republicans like Gingrich because A) he’s not Mormon, and B) he’s less incompetent, bumbling and crazy than the rest of the candidates.