Although John A. Boehner and the Republicans are coming off what is widely being scored as a victory on the argument over the 2011 budget, they risk overconfidence as Congress turns its attention to the next debate, the fight over raising the federal debt limit.

Perhaps the most important piece of reporting that you’ll read on the debt limit debate is this one, from The Times’s Jackie Calmes:

The Republican leader, Senator Mitch McConnell of Kentucky, has privately urged the conservatives not to filibuster, without success, say three people familiar with the talks. He argued that if Republicans did not filibuster and just 50 votes were needed for passage, the Republicans could try to force all the votes to come from the 51 Democrats — including 17 who are up for re-election. But if 60 votes are required because of a filibuster, ultimately some Republicans would have to vote for the increase lest the party be blamed for a debt crisis.

Philip Scott Andrews/The New York Times

Mr. McConnell is discouraging his colleagues from filibustering a vote to increase the federal debt limit because he knows that, if push came to shove, some of his colleagues would almost certainly have to vote yea. He’d rather it pass in a 51-vote environment, where all of the votes could come from Democrats, than in a 60-vote environment, where at least seven Republicans would have to agree to a cloture motion.

Although Mr. McConnell’s remarks were made privately, other prominent Republicans have said as much publicly (including Mr. Boehner, who has said that failing to raise the debt limit would create a “financial disaster,” and that the G.O.P.’s designated budget hawk, Paul Ryan, who has remarked that the debt ceiling must be raised and will be raised.)

That doesn’t sound like much of a negotiating position. How to reconcile it against comments from other Republicans, like Eric Cantor, that the debt ceiling vote will provide Republicans with “leverage” to extract additional policy compromises from President Obama and the Democrats? The obvious answer is that Republicans are running a bluff.

If Congress does not vote to increase the debt ceiling — a statutory provision that governs how many of its debts the Treasury is allowed to pay back (but not how many obligations the United States is allowed to incur in the first place) — then the Treasury will first undertake a series of what it terms “extraordinary actions” to buy time. The “extraordinary actions” are not actually all that extraordinary — at least some of them were undertaken prior to six of the seven debt ceiling votes from 1996 to 2007.

But once the Treasury exhausts this authority, the United States would default on its debt for the first time in its history, which could have consequences like the ones that Mr. Boehner has imagined: a severe global financial crisis (possibly larger in magnitude than the one the world began experiencing in 2007 and 2008), and a significant long-term increase in the United States’ borrowing costs, which could cost it its leadership position in the global economy. Another severe recession would probably be about the best-case outcome if that were to occur.

A second recession would almost certainly hurt Mr. Obama’s re-election chances, regardless of how articulate he is about trying to pin the blame on the Republicans. But it would also hurt virtually every other incumbent, including the Republicans (and likely also the Democrats) in Congress.

While it’s hard to know exactly what the political consequences might be — a debt default has never happened — some combination of the following might occur:

1. Mr. Obama would be significantly less likely to win a second term; 2. Mr. Boehner, Mr. Cantor, Mr. McConnell and other Republicans would have more difficulty retaining their leadership positions in Congress; 3. All incumbents would have more difficulty winning re-election, both because of the magnitude of the policy disaster and because the debt default (in addition to hurting the poor) would have a large impact on wealthy individuals and corporations, who are important to fund-raising; 4. Similarly, all incumbents, including Mr. Obama, would become significantly more vulnerable to primary challenges; 5. The two major parties would be significantly discredited and might fracture, possibly leading to the rise of a credible presidential candidate from a third party, or a spin-off of one of the existing parties; 6. A Constitutional crisis might ensue, because the Treasury has contradictory obligations in the event of a debt default with few clear rules (and no precedent) to guide them; 7. The challengers that were elected in 2012 would have significant difficulty retaining their seats in 2014 and 2016 because the fiscal crisis brought on by the debt default would probably last for several years and would lead to extremely unpopular austerity measures — so any immediate-term gains by either party could prove fleeting.

In short, this as close as you can get in American politics to mutually assured destruction. No matter how Machiavellian your outlook, it’s very hard to make the case that any politician with a significant amount of power would become more powerful in the event of a debt default. They also would be harmed personally, since many in Congress have significant investments in credit, stock or housing markets, all of which would be adversely affected.

A lot of the reporting I’ve seen on the debt limit vote, especially in those publications that focus more on politics than policy, has portrayed it as a zero-sum game. That’s the wrong characterization. In contrast to a government shutdown — which could have some negative consequences for incumbents of both parties, but not ones so large that they couldn’t be outweighed by strategic considerations — a debt default would be a bigger emergency by at least an order of magnitude. Its consequences are also much less linear and much less predicable than those of a government shutdown: you can’t partially default any more than you can be half-pregnant.

Now, that doesn’t mean that Republicans won’t be able to extract any concessions at all out of the Democrats. It’s possible that the White House — which has been risk-averse in recent months as it has focused on Mr. Obama’s re-election — might not be willing to take the chance of something going wrong. It’s possible that the White House could give the Republicans some concessions that they viewed as minor, inevitable, or actually desirable from a political and policy standpoint.

But Mr. Boehner may face just as much risk as Mr. Obama, if not more. He has promised his more conservative members that he will extract significant concessions from the Democrats before he agrees to an increase in the debt limit. A White House that was willing to play hardball could put him to the test, and perhaps cause a substantial loss of face.

I don’t know that this particular (and rather cautious) White House is likely to do that. But the equilibrium outcome is probably some fairly token concessions — enough to provide Mr. Boehner with some cover with the Tea Party but not much more.

That’s assuming, of course, that both sides play the “game” optimally, which is far from assured. If Mr. Obama is a good poker player, he’ll know not to disregard Mr. Boehner’s earlier rhetoric, which gave away the vulnerability of his hand. And he’ll recognize Mr. Boehner’s more recent and more confident rhetoric for what it is: the oldest “tell” in the poker book, a show of strength betraying the ultimate weakness of his position.