Matt Lewis of the Daily Caller summarizes it as well as we’ve seen anybody do:

A lot of people I talk to can’t fathom why Newt Gingrich is actually winning. The latest narrative–and I think there’s truth in it–is that voters are hungry for someone who will “take it to Obama.” Clearly, Gingrich’s debating ability is key. Republicans are champing at the bit to see him debate Obama. But I think this urge is deeper than a desire to simply watch him beat up or attack the president rhetorically–they also want him to intellectually flatten him–to out-debate him.

The left has a different set of explanations for Gingrich’s rise. Former Enron adviser Paul Krugman says it’s because GOP voters are “totally clueless” and “committed to demonstrably false beliefs.” E.J. “Baghdad Bob” Dionne says the “Republican establishment” has “sold its soul to the Tea Party” and “sat by silently as extremist rhetoric engulfed the GOP.” Krugman colleague Charles Blow says it’s because the GOP is “bankrupt of compassion and allergic to accuracy.”

While these statements are all foolish and obnoxious, they fit right into our thesis. Gingrich is popular among conservatives because he refuses to be browbeaten by liberal bullies. One can easily imagine him bringing out the least attractive qualities of Obama, who does not like to be challenged.