Former House Speaker Newt Gingrich has turned his skill at debating into his central argument for the GOP nomination — but it’s not clear he has an airtight case.

Over and over, he’s repeated that he alone can best President Obama in debates and win the presidency in the process. But in making the argument, he’s ignoring both history and, perhaps most importantly, a good look in the mirror.

{mosads}To hear Gingrich tell it, voters are going to waltz into the voting booth on Nov. 2 and make their decision based on three things — who won the first general-election debate, who won the second, and who took the third. And Gingrich has been relentless in pitching that notion.

After a series of strong debate performances propelled him to a win in South Carolina’s primary, he told CNN that he would win Florida the same way.

“My job in Florida is to convince people that I am the one candidate who can clearly defeat Obama in a series of debates. … One of the reasons people in South Carolina voted for me was a belief that I could debate Obama head to head,” he said.

On that, Gingrich is right. In CBS exit polls of the South Carolina contest, more than 60 percent of voters said the debates had played an important role in their decision. And, in a dramatic reversal, a Rasmussen survey on Monday showed that Republicans now think Gingrich is slightly more likely to beat Obama in a general election than is former Massachusetts Gov. Mitt Romney. And that could be because of Gingrich’s forensic skill.

Gingrich has also pounded this theme into voters’ heads over the airwaves. One commercial in South Carolina focused entirely on his debate performances, while an ad released this week leads off with polemics playing the primary role.

The narrator asks: “Which of the Republican candidates for president has the knowledge, experience and capability of debating one on one with Barack Obama and winning?”

Why, Gingrich, of course.

To that end, Gingrich has constantly promised GOP voters that he’ll challenge Obama to seven three-hour debates, and that Obama won’t be able to “survive” them. 

But there are a few complications for Gingrich’s argument.

Seven debates is a pipe dream

There’s nary a soul alive who thinks Obama will actually answer Gingrich’s challenge and commit to seven three-hour debates. That’s unprecedented in modern history. 

Plus, the commission on presidential debates has already announced its 2012 schedule, and it features three meet-ups, similar to the way debates worked in 2008.

Besides, which network would award the candidates 21 hours of primetime TV?

So, on that score, Republicans probably shouldn’t pin too many hopes on Gingrich.

General-election debates don’t matter too much

Larry Sabato, director of the University of Virginia Center for Politics, explains why general-election debates aren’t nearly as influential to the final outcome as primary debates.

In the primary debates, “all the candidates are Republicans and the vast majority of voters are Republicans. Therefore, it is easier to transfer support via a debate from one Republican to another,” he said.

Meanwhile, in the general-election debates, “over 90 percent of the voters have a partisan ID, even if it is hidden. Changing from Democrat to Republican or Republican to Democrat is quite a jump.”

Dartmouth Professor Brendan Nyhan, a New York Times best-seller and media critic, agrees with the sentiment and claims that “the importance of debates tends to be overemphasized by journalists trying to construct dramatic narratives.”

And there’s one more reason why general-election debates are likely to be less important than the primary duels. Over the course of the general, there will probably be three debates. So far, there have been 18 primary debates. Consequently, debate performances will be far fresher in people’s minds during the primaries.

Gingrich’s debating skills are overrated

Brad Phillips, the president of Phillips Media Relations and author of the Mr. Media Training blog, thinks Gingrich’s style won’t play when he’s trying to sell general-election voters on his candidacy — and nowhere will that be more evident than in the debates.

“Since the beginning of the 24/7 media age in 1980, the sunnier and more optimistic candidate has won all eight general elections,” Phillips points out.

{mosads}Indeed, the list of losers is littered with the gloomy and doomy — Walter Mondale, Mike Dukakis, George H.W. Bush in 1992, Al Gore, John Kerry and John McCain.

Gingrich errs on the side of the irascible; indeed, Sabato notes, one voter left the polling booth in South Carolina saying, “I think we need somebody mean.”

That’s not to say that Gingrich is a mean or bad person. It’s just that he tends to be rhetorically confrontational. It’s a style that plays well if you agree with him, but runs the risk of alienating undecided voters.

Now, to be sure, Gingrich isn’t basing his entire campaign on the prospect of winning debates against Obama. He frequently talks of “big issues” requiring “big solutions” that are anything but the fluff that usually dominates debates. 

But, more than any other candidate in modern history, he’s wooed Republicans through the hope of making Obama sweat on the stage. 

Should Republicans sweat that promise?

Heinze, the founder of GOP12.com, is a member of staff at The Hill.

— This column was updated at 9:52 a.m.