One test of a presidential contender is what the average voter can say about why to support him or her in two sentences or less. I’d suggest that “because he can win” is not really a sufficient reason, which should be troubling for Mitt Romney in light of what just happened in South Carolina.

A successful candidate must be clearly defined in the average voter’s mind—simply winning, or the prospect thereof, doesn’t delineate a candidate. 

Think back to successful presidential candidates. It was easy for voters to define, say, Ronald Reagan or Bill Clinton. They met the two-sentence-or-less test. But how does the average person encapsulate Romney or Newt Gingrich, now the two top contenders for the GOP nomination? During my time as a sitcom writer, it was my job to get into the mind of the American public by creating likeable, or at least memorable, characters. So, on the job again, what about the public and the GOP field?

Romney reminds me of the guy every gal wanted to date in high school. And no question he must be smart, after all he went to Harvard Law and Business school. But can we define him with those skills? Nope. He doesn’t mention what skills he got there, presumably because it doesn’t sound appealing to the average voter.

So what does that leave us with? He’s got money, and yet pays less tax than most of us do. He says he was a job creator, but that probably doesn’t wash with Mr. and Mrs. America, either, because we don’t have a clue what jobs he actually created. (Pity that business school education hasn’t come into play in his speeches.) I’d actually like to hear the processes he went through to create the jobs he said he did. And so what if he’s rich?

Most of us wouldn’t mind a few million. But how’d he do it, really? It’s not easy to define why one likes Mitt. Sadly, it’s much easier to pinpoint why one doesn’t. Like when he said he earned more than $300,000 in speaking fees in 2010, but called that “not very much.” To whom? Donald Trump?

Meanwhile, Gingrich definitely has an image problem. The often red-faced former Speaker carries an air of anger about him, as if he’s thinking: “I’m going to confine myself to my fabulous and patronizing vocabulary for now, but really I’m going to explode on you the minute this broadcast is over.”

Take, for instance, how he sounded out moderator Juan Williams’ name—“Juaaan”—during the second to last debate before the South Carolina primary. Talk about barely concealed anger. Of course, Gingrich’s anger was even more apparent last Thursday when CNN’s John King opened with a question about his ex-wife. Given his margin of victory on Saturday, mind you, it could be that being defined as angry is a good thing in 2012.

One question, though, how does someone run a tab of a half million bucks at Tiffany & Co.? That’s not a line item for most of us, and if it is, I have to tell my husband. There are a couple of gems I have my eye on. Tab now, pay later? Isn’t that what got us into this mess in the first place?

If I was still in the sitcom biz and I wrote a lead character that no one liked, but remembered in a way you didn’t want, you know what would happen to my series? Canceled. Yeah.

If I were a Republican, I’d worry about stuff like that.

Jennie Blackton is a former talk-show host, sitcom writer/producer and movie studio vice president. She now works with down-ballot candidates on their communication. In the last 12 years, her work has helped several hundred winning candidates.