The Republican Party, after converting huge surpluses into huge deficits during the Bush era, after opposing deficit-reducing health reforms, student loan reforms and big-bank taxes during the Obama era, after continuing to clamor for trillions of dollars in deficit-expanding tax cuts while gutting House pay-as-you-go rules to make it easier to expand the deficit, has somehow managed to re-brand itself as the party of fiscal responsibility. It’s a remarkable political achievement.

It’s also useful context to discuss the increasingly urgent warnings by watchdogs like Congressional Budget Office director Doug Elmendorf and Federal Reserve chairman Ben Bernanke that a U.S. debt default would have catastrophic fiscal as well as economic consequences. It would increase our borrowing costs. It would decrease our revenues. How to put this diplomatically? Uh…THE GOP DOESN’T CARE! As long as it doesn’t get blamed for those consequences.

(MORE: Debt Limit Talks Enter Crunch Time But Negotiators Remain Far Apart)

It’s an outrageous situation, and I’ve certainly banged my spoon on my high chair about it. But it’s the situation we’re in. And Republicans are behaving perfectly rationally; they haven’t paid a political price for hypocrisy or irresponsibility in the past, so why shouldn’t they threaten to force a default unless President Obama adopts their agenda? Why shouldn’t they hold the full faith and credit of the U.S. government hostage, if voters will blame Obama for the results? Why shouldn’t they give pious speeches about the tragedy of the debt they created themselves?

The last time I argued with David Von Drehle about this stuff, he ended up (as usual) conceding I was right and claiming he had secretly agreed with me all along. But while I don’t plan of making a habit of saying things like this, his final point made a lot of sense: Republicans have been able to make political hay out of the deficit despite the fiscally profligate Bush era—and, David forgot to mention, despite continuing their fiscally profligate ways—because Obama has failed to make his political case.

(MORE: On Deficits and Debt, the Voters Get a Say)

Respected independent watchdogs Elmendorf and Bernanke actually provided an excellent reminder of Obama’s political failures, because they both argued against short-term budget austerity that could hurt the economy, while urging a credible long-term fiscal plan. In other words, they argued for what Obama wants, and against what the Republicans want. Most credible economists do. But the national conversation has been all about short-term austerity. That’s not just bad for Obama politically; that’s bad for the country economically.

It’s not Obama’s fault that Republicans are irresponsible. But he’s not powerless. He’s not voiceless. It was no coincidence that when he laid out a strong case against GOP fiscal insanity in his George Washington speech in April, Republicans hated it, screeching that he was the meanest, nastiest, most partisan President in the history of Kenyan sharia socialism. Apparently, he touched a nerve. But he hasn’t touched it again. Ultimately, if he can’t create a political atmosphere where irresponsibility is punished, the irresponsibility will continue. And he’ll be held accountable for the consequences.

PHOTOS: Republican Memorabilia