Susan Walsh / AP President Barack Obama speaks at the James Lee Community Center in Falls Church, Virginia, Feb. 1, 2012.

Newt Gingrich ended his campaign against Mitt Romney in Florida with the same message strategy that Romney’s senior advisers had used in another Republican primary two years earlier: Attack Goldman Sachs. There was a good reason.

Amid the orange groves and senior centers, the successful investment bank served as Gingrich’s red meat for the right. “You look at Goldman Sachs, which was the number one funder of Obama; now they’re the number one funder of Romney,” he told CBS News, just a day before the polls closed. “I think it’s pretty easy to make the case Romney is the guy who will manage the decay.”

The echoes were unmistakable. In 2010, Romney’s current pollster, Neil Newhouse, and top ad man, Stuart Stevens, had employed a nearly identical strategy when attacking a Republican frontrunner, Meg Whitman, in the California gubernatorial primary. “Goldman executives donated over $100,000 to Whitman,” ran one of the ads, for Steve Poizner, called “Vulture.” “Meg Whitman: Bad judgment. Wrong values.”

The reasons for the matching strategies speak to a central shift that has occurred in the national electorate, and the Republican Party, since the 2008 economic collapse. Economic populism—the idea that the many have been fleeced by the rich few–is no longer just a Democratic argument, which can be used to attract blue collar independents in the Midwest. It now works deep in the Republican ranks, having been first adopted by the no-bailout, Washington corruption message of the Tea Party in 2009.

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Shortly before the New Hampshire primary took place, leaders of Priorities USA, the pro-Obama super PAC, tested messages among Republicans in South Carolina to explore the best way to attack Romney. What they found surprised them. Among Republicans with only a high school diploma, 67% admitted to greater doubts about Romney when read a statement about layoffs at Romney’s former firm, Bain Capital. When read a statement about Romney paying lower taxes because of his investment income, 62% of high school graduates said they had greater doubts about Romney. College graduates, by contrast, were less impressed, saying they were swayed by the messages by 42% and 41%, respectively.

Those same trends have been seen nationally. In a December NBC/Wall Street Journal poll, voters were asked to respond to a statement that read, “The current economic structure of the country is out of balance and favors a very small proportion of the rich. America needs to reduce the power of major banks and corporations and demand greater accountability and transparency. The government should not provide financial aid to corporations and should not provide tax breaks to the rich.” Among Republican primary voters, 60% agreed, and 40% agreed strongly. The same proportions agreed among self-described Tea Party supporters. Among Independents, 79% agreed, and 62% agreed strongly.

A more recent Pew Poll found that 66% of Americans see a “very strong” or “strong” conflict in this country between the rich and poor. When asked by Pew if the wealthy pay their “fair share” in taxes, 38% of Republicans and 57% of independents say the answer is no.

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It is in this context that the Obama campaign has debuted a master campaign message that plays right into this class-based sense of injustice now roiling all sides of the ideological spectrum. This is the reason Obama has focused on the so-called Buffett Rule, which would raise taxes on some millionaires while having a minimum impact on the poor. It is why the President can hardly pass a microphone these days without calling on the rich to “pay their fair share.” It is why Obama has refurbished an old Bill Clinton line from 1992. “Let’s never forget,” he said in the State of the Union address. “Millions of Americans who work hard and play by the rules every day deserve a government and a financial system that do the same.”

Just how the Romney campaign responds, beyond decrying such comments as “class warfare” and “attacks on free enterprise,” is still an open question. But some Republican strategists and pollsters doubt that simply blaming Obama will be enough. Henry Olson, a conservative scholar at the American Enterprise Institute, argues that Republicans face a real challenge, that goes beyond the perceptions of Romney’s wealth and past. Working class white voters, he argues, have become increasingly alienated from the conservative policy agenda of spending cuts and continuing low taxes, just as they have been turned off by President Obama’s performance. “You are gambling that they will dislike Obama more than they disagree with you,” Olson said of the current Republican playbook.

But that is a question for another day. First the Republican primary will have to be resolved, and the early signs are that the economic populist attacks, from both Gingrich and Obama’s allies, are already taking its toll. A recent Washington Post poll found Romney dropping to 23% favorability rating among independents, from levels in the mid-40s last fall. Romney still has time to respond, but there is no doubt that he will have to forcefully.