Conservatives may denounce class warfare, yet by shrewdly combining the politics of class with the politics of culture, Newt Gingrich won his first election in 14 years, humbled Mitt Romney and upended the Republican Party.

He also exposed profound frailties in Romney as a candidate, throwing him badly off-balance on questions related to his personal wealth, business career and income taxes. Unless Romney finds a comfortable and genuine way of talking about his money, he will present President Obama’s team a weakness that they’ll exploit mercilessly. The country is thinking more skeptically about wealth and privilege in the wake of the Occupy Wall Street protests. Romney has not adjusted.

Gingrich skillfully set up his opponent to step on the landmine of class by transforming Romney from his self-cast role as a successful businessman into a heartless financier more interested in profits than in job creation.

The conventional view is that Gingrich’s critique of Bain Capital, Romney’s old company, didn’t work because Republicans dislike assaults on “free enterprise,” a phrase Romney still hopes to use as a self-protective mantra. But while Gingrich softened his attacks on Bain, he did so only after creating the context in which Romney was forced to answer query after query about his financial status, and he repeatedly fumbled questions about releasing his tax returns. Romney finally announced Sunday he’d make public his 2010 return and a 2011 estimate this week.

All this allowed Gingrich to draw a class line across South Carolina. Exit polls showed Romney carrying only one income group, voters earning more than $200,000 a year. Voters earning less than $100,000 a year went strongly for Gingrich.

Yet conservative class politics is always inflected by culture and ideology, the potent mix that Pat Buchanan brought to Richard Nixon’s attention four decades ago. South Carolina’s two debates offered Gingrich a showcase for his war on those elites whom the conservative rank-and-file despise.

There was also the matter of race. Gingrich is no racist, but neither is he naive about the meaning of words. When Fox News’ Juan Williams, an African-American journalist, directly challenged Gingrich about the racial overtones of Gingrich’s staple reference to Obama as “the food-stamp president,” the former House speaker verbally pummeled him, to raucous cheers. As if to remind everyone of the power of coded language, a supporter later praised Gingrich for putting Williams “in his place.”

Then came the rebuke to CNN’s John King, who asked about the claim from Gingrich’s second wife that her former husband had requested an “open marriage.” By exploding at King and the contemporary journalism, Gingrich turned a dangerous allegation into a rallying point. Past sexual conduct mattered far less to conservatives than a chance to admonish the supposedly liberal media. Gingrich won evangelicals by 2-1, suggesting, perhaps, a rather elastic definition of “family values” — or a touching faith in Gingrich’s repentance.

With unremitting attacks on Romney as a “Massachusetts moderate,” Gingrich created yet another link between his opponent and elite Yankees loathed by the Southern right. He reaped landslide margins among conservative groups, marginalizing the buttoned-down, less electric Rick Santorum.

There were also hints in exit polling that hostility to Romney’s Mormon faith may have added to his troubles, without help from Gingrich. About a quarter of South Carolina’s voters said a candidate’s religious beliefs mattered a “great deal” to them, and Romney secured a scant 10 percent of their ballots.

If there is solace for Romney, it is in the experience of an earlier front-runner. In late March 1992, the day before the Connecticut primary, I found myself standing with a colleague next to Bill Clinton in a coffee shop in Groton. Clinton surprised us by suggesting he would lose the next day to Jerry Brown, now California’s governor. Voters were in an ornery mood, he said, and many of them wanted to declare: “I don’t want this to be over.”

Clinton was right. He lost Connecticut. Yet two weeks later, he swept a series of primaries, including a decisive contest in New York.

Florida, which votes next on Jan. 31, is Romney’s New York. But there is a difference. Clinton was a master campaigner with what has quaintly been called the common touch. Romney has so far proved himself to be more a master of discomfort and unease, especially with his own wealth. Unless he learns how to navigate the country’s new etiquette about financial privilege, Romney will continue to be plagued by the now twice-resurrected Gingrich — and, if he survives Gingrich’s challenge, by a freshly minted populist named Barack Obama.

ejdionne@washpost.com