For an increasingly uphill re-election battle in which he’ll have to “go negative,” I’d figured President Obama would imitate Harry Truman in ’48, railing against a “do-nothing Congress.” But it turns out he’ll be running as Teddy Roosevelt instead.

Obama wrapped himself in T.R.‘s mantle in a much-hyped speech last Tuesday in Osawatomie, Kansas. There, in 1910, ex-president Roosevelt proclaimed a “New Nationalism” that would involve “far more active governmental interference with social and economic conditions in this country than we have yet had.” He’d go on to challenge President Taft for the Republican nomination, and then run as a Progressive when that failed.

Modeling your re-election strategy on an obnoxious authoritarian’s failed third-party run for the presidency a hundred years ago is an interesting choice, but not necessarily a wise one. It’s a move of desperation, unlikely to work.

GOP front-runner Newt Gingrich calls himself “a Theodore Roosevelt Republican.” Despite (or because of?) T.R.‘s many flaws, politicians from both parties have long found something irresistible about our pulpit-pounding 26th president.

But T.R.‘s enduring appeal is an enduring mystery. What’s so attractive about Roosevelt’s political philosophy? A loudmouthed cult of manliness? A warped belief that war is a good tonic for whatever ails the national spirit? A contemptuous attitude toward limits on presidential power?

The late-stage T.R. — the version Obama has chosen — is a particularly unappealing model. Out of power, T.R. became increasingly unhinged and radical, proclaiming in 1911 that “we must abandon definitely the laissez-faire theory of political economy, and fearlessly champion a system of increased governmental control.”

After losing the 1912 race, Roosevelt finished out his career calling Woodrow Wilson a coward for not getting us into World War I quickly enough. “This last phase,” biographer Lewis Gould notes, “with Roosevelt almost a parody of his former self attested to how his charisma had curdled in the concluding decade of his public life.”

Yet Osawatomie Obama’s policy prescriptions aren’t nearly as radical as Roosevelt’s were a century ago. President Obama offered a familiar mix of higher taxes on the “1 percent,” tighter financial regulation, and more government “investment” in infrastructure and education. This is pretty thin soup for the Progressive soul.

The “New Populism” is also unlikely to solve Obama’s political woes.

The last economic-populist campaign for the presidency was a flop, as anyone who recalls Al Gore’s monotonous 2000 refrain of “the people versus the powerful” can attest. With even his running mate, Joe Lieberman, conceding that the appeal hurt the campaign, in 2002 Gore penned a defensive op-ed in the New York Times, insisting that “Standing up for ‘the people, not the powerful’ was the right choice in 2000.”

Obama’s strategists believe Populism has a better chance in a stalled economy. Perhaps, but you go to class warfare with the candidate you have, and Obama is a spectacularly lousy demagogue.

In his Washington Post column a few months back, “Mr. Cool Turns Cold,” Richard Cohen told what he considers a moving story about T.R.‘s cousin, Franklin Roosevelt, weeping in the Oval Office about the plight of migrant workers. “Can anyone imagine Barack Obama doing anything similar?” Cohen asks.

No, and that’s fine with me. We don’t need an Empathizer-in-Chief. That Obama is visibly uncomfortable pretending he “feels your pain” is one of the only redeeming facets of his public persona.

But Cohen may be right that it’s an electoral handicap for a would-be economic populist: “He could be defeated because he is cold.”

Even in hard times, class warfare remains a hard sell in America. And this president just can’t sell it.