President Obama came to this small middle-America town Tuesday to invoke the spirit of a long-ago Republican president in a speech that laid out, in his sharpest language yet, the economic and social arguments he likely will use in 2012.

OSAWATOMIE, Kan. — President Obama came to this small middle-America town Tuesday to invoke the spirit of a long-ago Republican president in a speech that laid out, in his sharpest language yet, the economic and social arguments he likely will use in 2012.

Obama called for a return to modest, middle-class values and said the recent rise in populist anger — from the tea-party movement to the Occupy Wall Street protests — was evidence of the need to remedy the growing economic inequality in American life.

The president chose this town of 4,600 in eastern Kansas as a historical echo of a speech given more than a century earlier by Theodore Roosevelt, who used the same location to call for a strong central government that would protect ordinary Americans from what he called the greed and recklessness of big business and special interests. That speech, which became known as “the New Nationalism” speech, was one of the early cornerstones of 20th-century progressivism.

Obama, in a 55-minute address, moved beyond specifics of his recent jobs proposals to issue a searing indictment of Republican economic theory, framing the economic debate as one of right and wrong, fairness and unfairness.

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“This is the defining issue of our time,” Obama said before a crowd of 1,200 at the high-school gymnasium. “This is a make-or-break moment for the middle class, and all those who are fighting to get into the middle class. At stake is whether this will be a country where working people can earn enough to raise a family, build a modest savings, own a home, and secure their retirement.”

The speech comes at a moment when a new populist strain seems to be bubbling through the national political debate, from city halls to statehouses to Washington.

That debate, dominated not long ago by concern about the national debt and the size of government, seems to be shifting.

In one example of the shift, New York Gov. Andrew Cuomo, a Democrat, reached an agreement with the Legislature on Tuesday to overhaul the state’s tax code, creating a higher tax bracket for wealthy earners while cutting taxes for the middle class. Democratic legislators said the aim was to restore fairness to the tax code, echoing Obama rhetoric.

Also Tuesday, radio host Glenn Beck chastised GOP presidential candidate Newt Gingrich about his 2003 declaration that he considers himself a “Theodore Roosevelt Republican.” Gingrich defended the label on Beck’s show and said he believes there are “minimum regulatory standards of public health and safety that are, I think, really important.” Gingrich quickly distanced himself from the later Theodore Roosevelt, who Gingrich said had become, by 1912, a “big-government, centralized-power advocate running as a third-party candidate.”

For Obama, the day marked another milestone in his recent political evolution after the disastrous debt-ceiling negotiations last summer.

Criticized by allies who said he had been too willing to compromise or simply had capitulated, Obama has tried to become a more pugilistic champion of the middle class as he gears up his re-election campaign against a Republican Party that he hopes to paint as a defender of the wealthy.

He repeatedly blamed the nation’s economic woes on what he described as corporate greed, citing, as collateral damage, a “deficit of trust between Main Street and Wall Street.” And he lambasted his Republican adversaries for their eagerness to roll back financial regulations and return to policies that caused the market crash.

“Their philosophy is simple: We are better off when everyone is left to fend for themselves and play by their own rules,” Obama said. “Well, I’m here to say they are wrong. … We shouldn’t be weakening oversight and accountability. We should be strengthening them.”

With so much attention devoted to the Republican primary contest in recent days, Tuesday was an opportunity for Obama to lay down a marker against the potential Republican nominees. His Kansas speech drew quick rebukes.

Former GOP presidential candidate Tim Pawlenty, playing off Roosevelt’s “Square Deal” economic program, said Obama has given Americans a “raw deal.”

“When we think of former presidents, Barack Obama reminds me not of Teddy Roosevelt but of Jimmy Carter,” said Pawlenty, who has endorsed former Massachusetts Gov. Mitt Romney for the GOP nomination.

Analysts said Obama’s eagerness to channel Republican presidents such as Theodore Roosevelt, as well as Abraham Lincoln and Ronald Reagan, is aimed at marginalizing the current brand of Republicanism as a product of extremists and partisan ideologues.

Obama is “trying to show how far the Republican Party has strayed,” said Allan Lichtman, a U.S. history professor at American University. He is “trying to draw a contrast between a narrow, cramped, corporate Republican Party and the party of Lincoln and Roosevelt that sought liberty and represented ordinary people.”

Still, Obama delivered a searing indictment of core Republican economic theory, with the GOP brand of “trickle-down economics” drawing some of the harshest criticism.

That theory, which holds that greater wealth at the top generates jobs and income for the masses, “speaks to our rugged individualism and healthy skepticism of too much government,” Obama said. “It fits well on a bumper sticker. Here’s the problem: It doesn’t work. It has never worked.”

Obama’s speech rang true to the partisan crowd in a deeply red state.

Audra Kelley, 31, an anti-domestic-violence advocate from nearby Lawrence, was wearing an Occupy Wall Street button that read: “We are the 99% and we’re too big to fail.” She empathized with Obama’s inability to advance his agenda.

“If the things that he has been trying to do weren’t blocked by obstructionists, we’d be a lot farther down the path to a better economic situation,” Kelley said. “The Republican Party is doing their best to stop anything, even if it’s something they supported 10 years ago. We need to just get back to trying to figure out what’s good for the entire country, not just the superrich.”

Washington Post reporters Anne Kornblut and Philip Rucker contributed to this report.