There was a moment during his victorious primary campaign in South Carolina in January when Barack Obama was saying something isn’t right and a guy in the crowd shouted: “Ain’t right, Barack, ain’t right.”

I didn’t think much of this isn’t-versus-ain’t thing at the time, but it’s been on my mind here at the Democratic National Convention because the whole production, so far, has been mainly about demonstrating that Obama’s a regular guy from Main Street, U.S.A. -- and that ain’t no made-up story.

Sure, there are issues. There’s a middle class mauled by $4-a-gallon-plus gas, soaring health costs, Bangalored jobs and lost homes -- while the rich got tax breaks.

But if the economy now trumps Iraq, I’d say personality still trumps the economy. In the end, the election will be about trust and authenticity.

At least 80 percent of Americans think the country’s going in the wrong direction, one set by Republicans in the White House for all but 12 of the last 40 years. So the result in November should be a no-brainer: change, the word that has propelled Obama this far.

In the last few weeks, however, as Obama’s lead in the polls over the Republican candidate, John McCain, has all but vanished, that logic has frayed. Obama’s got some connection issues.

He’s been unable to push significantly beyond the yes-we-can fervor of his broad band of followers into the skeptical white, blue-collar America that favored Hillary Clinton and whose support he needs.

He’s been Denzel Washington playing the reassuring, handsome attorney on a stirring moral mission, reaching across enough barriers of race and class to get within sight of the White House. But can he now moderate that polished image to spread his appeal to the meat-and-potatoes crowd?

Is Obama more beer than Chardonnay? Is he a Dunkin’ Donuts or Starbucks guy? Must he talk fancy? Is he one of us despite having what his wife Michelle called “that funny name?”

That’s been the subtext of this convention, and Hillary’s people have not been discouraging it.

The funny-name reference came in Michelle’s touching speech on the convention’s opening night, a tribute devoted to answering those identity questions by evoking a basketball-playing, loving, industrious, idealistic, constant husband devoted to his daughters and driven to rise from adversity by a dream of opportunity for all.

Yes, it was touching, but it was also a little cloying.

Again I found my mind going back to South Carolina where Michelle’s heels were higher, outfit bolder, and tone more forthright. Since then, with her pride in America questioned, she’s been choreographed toward the demure in the interests of placing the family in the mainstream.

“I saw a very interesting, complex woman who had been reduced to saying what a good mom she was and how cute her meeting with Barack was,” said John McWhorter, a senior fellow at the Manhattan Institute. “It was sincere, but I found myself cringing.”

McWhorter thinks Obama must remember that “being reflective will not get him elected.” Strong, focused and memorable is the tone he needs, as in Bill Clinton’s line on affirmative action: “Mend it, don’t end it.” In recent weeks, reading Obama’s lips on everything from the Russian invasion of Georgia to the rights of fetuses has been tough.

The fact Obama is under such pressure reflects Republican success since Reagan in framing Democrats as weak, unpatriotic, indecisive Volvo-driving nerds. “Conservative populism has successfully cast the liberal elite as looking down on the values of ordinary Americans,” said George Lakoff, a political theorist.

The best response to that is reality. Ordinary Americans are debt-ridden and struggling and values won’t pay their bills. Obama has been eloquent in describing this and proposing a new inclusive politics.

Eloquence, however, isn’t for everyone. He has not made an issue his own -- not even energy -- or found the one-liner to frame it.

But ain’t all this dumb? Here’s Obama, just finished with paying off his student loans, having to prove that he’s more mainstream than seven-house McCain, who’s just learning “to get online myself,” as he told my colleagues Adam Nagourney and Michael Cooper, and leaves e-mail to minions.

Dumb as in John Kerry, four years ago, having to prove his patriotism when he’d fought in Vietnam while George W. Bush fooled around Texas.

But that’s where Obama is: it’s hardball now. Hillary Clinton can broaden his constituency, but will she? Her support for him on the convention’s second night seemed more of form than spirit, devoid of personal affection. Bill Clinton was far more effusive.

The difference from 2004 is that the country is deep into economic plight, deeper into two wars, and weary of Republican fear-mongering. It may even be ready for what Mark Greenwood, a lawyer from Dickinson, N.D., called “someone who knows how to speak the English language.”