DES MOINES, Iowa » The 2012 presidential election, Mitt Romney said Thursday, "could be our last chance" to save the United States from Greece-like bankruptcy.

The nation, he said, is "only inches away from no longer being a free economy." The task ahead, he proclaimed at another campaign stop days before the Iowa caucuses kick off the Republican primary season, was nothing less than "saving the soul of America."

Romney is hardly alone in elevating the stakes of the presidential race to levels approaching survival of our way of life.

"I believe this election is the most important election since 1860," Newt Gingrich said recently. Jon M. Huntsman Jr. is a bit more restrained; to him, it is only the most important of his lifetime, or maybe since the Depression.

"This election is about whether America and its very essence will continue, whether it will be free and safe and prosperous," Rick Santorum said this fall.

On one level, the politics of apocalypse avoidance are straightforward. In a Republican party whose conservative base views President Barack Obama as determined to replace market forces with government mandates and intent on apologizing for the United States around the world, many voters feel that something fundamental is on the line and want to know their candidates feel the same way. And the more Republicans feel is on the line, the greater the likelihood that they will turn out to vote.

But the future-of-civilization approach also carries risks for the eventual Republican nominee, and not just because moderate and independent voters might judge it to exaggerate Obama’s shortcomings.

What is under way now is a contest to define what the election is about. Even as the Republican candidates have been fighting it out among themselves in an ever-shifting primary campaign, Obama has been ramping up his effort to make 2012 a clash of competing visions about how to ensure a future for the American middle class. In the process, he is also working to define what the election is not about: the persistently high unemployment rate and his inability to point to hope for a robust economic recovery.

Seeing an opportunity to engineer a lasting and fundamental change in Washington’s ideological direction, Republicans are choosing to play along, seeking a mandate, in framing the election as historic, to do more than just oust Obama.

Where Republicans warn of class warfare, Obama is talking about income inequality. Where Republicans cite the perils of over-regulation and the heavy hand of government, Obama invokes consumer protection and the destructive excesses of the financial system.

Where Republicans see looming Democratic tax increases, Obama sees equitable burden-sharing. Where Republicans portray Obama as European in his sensibilities if not downright un-American, the president casts himself as a modern-day Teddy Roosevelt.

At the White House, Obama’s advisers are confident that this is an opportune moment to define a choice of starkly different visions for the future, and in doing so avoid a referendum on the economic troubles of the moment.

After a period in which the anti-Washington, budget-cutting fervor of the Tea Party movement moved the center of gravity in American politics to the right, the president and his team see a shift in the nature of the anger coursing through the electorate, toward a demand for fairness for the middle class.

"This is the defining issue of our time," Obama said in his speech in Kansas this month setting out the themes of his re-election campaign. "This is a make-or-break moment for the middle class, and for all those who are fighting to get into the middle class. Because what’s 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, secure their retirement."

Whether Obama can make his version of the stakes sufficiently urgent to win a hearing from frustrated voters remains an open question. His approval ratings seem to be ticking slightly upward, but they remain perilously low for an incumbent seeking re-election. An overwhelming proportion of Americans say the nation is on the wrong track.

Meanwhile, Republicans are honing their messages about the big issues in ways that give them a chance to make a connection with the anxiety among voters that the nation’s best days are behind us. "I’m not going to borrow money from China to pay for things that aren’t absolutely necessary," Romney said at a stop in Mason City, Iowa, on Thursday, linking his smaller-government argument to the debt burden being left to the next generation.

There is a long way to go in the campaign, and the Republican candidates would bring different strengths and weaknesses to a debate with the president over the size and role of government and the future of the middle class. But for now at least, Obama seems to be succeeding in making the election about something more than the monthly job-creation figures.

© 2011 The New York Times Company