In a merciful twist of fate, Juan Linz did not quite live to see his prophecy of the demise of American democracy borne out. Linz, the Spanish political scientist who died last week, argued that the presidential system, with its separate elections for legislature and chief executive, was inherently unstable. In a famous 1990 essay, Linz observed, “All such systems are based on dual democratic legitimacy: No democratic principle exists to resolve disputes between the executive and the legislature about which of the two actually represents the will of the people.” Presidential systems veered ultimately toward collapse everywhere they were tried, as legislators and executives vied for supremacy. There was only one notable exception: the United States of America.

Linz attributed our puzzling, anomalous stability to “the uniquely diffuse character of American political parties.” The Republicans had loads of moderates, and conservative whites in the South still clung to the Democratic Party. At the time he wrote that, the two parties were already sorting themselves into more ideologically pure versions, leaving us where we stand today: with one racially and economically polyglot party of center-left technocracy and one ethnically homogenous reactionary party. The latter is currently attempting to impose its program by threat upon the former. The events in Washington have given us a peek into the Linzian nightmare.

Traditionally, when American politics encountered the problem of divided government—when, say, Nixon and Eisenhower encountered Democratic Congresses, or Bill Clinton a Republican one—one of two things happened. Either both sides found enough incentives to work together despite their differences, or there was what we used to recognize as the only alternative: gridlock. Gridlock is what most of us expected after the last election produced a Democratic president and Republican House. Washington would drudge on; it would be hard to get anything done, but also hard to undo anything. Days after the election, John Boehner, no doubt anticipating things would carry on as always, said, “Obamacare is the law of the land.”

Instead, to the slowly unfolding horror of the Obama administration and even some segments of the Republican Party, the GOP decided that the alternative to finding common ground with the president did not have to be mere gridlock. It could force the president to enact its agenda. In January, Boehner told his colleagues he’d abandon all policy negotiations with the White House. Later that spring, House Republicans extended the freeze-out to the Democratic-­majority Senate, which has since issued (as of press time) eighteen futile pleas for budget negotiations. Their plan has been to carry out their agenda by using what they call “leverage” or “forcing events” to threaten economic and social harm and thereby extract concessions from President Obama without needing to make any policy concessions in return. Paul Ryan offered the most candid admission of his party’s determined use of non-electoral power: “The reason this debt-limit fight is different is we don’t have an election around the corner where we feel we are going to win and fix it ourselves,” he said at the end of September. “We are stuck with this government another three years.”

Last Tuesday, House Republicans shut down the federal government, demanding that Obama abolish his health-care reform in a tactically reckless gamble that most of the party feared but could not prevent. More surreal, perhaps, were the conditions they issued in exchange for lifting the debt ceiling later this month. Lifting the debt ceiling, a vestigial ritual in which Congress votes to approve payment of the debts it has already incurred, is almost a symbolic event, except that not doing it would wreak unpredictable and possibly enormous worldwide economic havoc. (Obama’s Treasury Department has compared the impact of a debt breach to the failure of Lehman Brothers.) The hostage letter House Republicans released brimmed with megalomaniacal ambition. If he wanted to avoid economic ruin, Republicans said, Obama would submit to a delay of health-care reform, plus tax-rate cuts, enactment of offshore drilling, approval of the Keystone pipeline, deregulation of Wall Street, and Medicare cuts, to name but a few demands. Republicans hardly pretended to believe Obama would accede to the entire list (a set of demands that amounted to the retroactive election of Mitt Romney), but the hubris was startling in and of itself.

The debt ceiling turns out to be unexploded ordnance lying around the American form of government. Only custom or moral compunction stops the opposition party from using it to nullify the president’s powers, or, for that matter, the president from using it to nullify Congress’s. (Obama could, theoretically, threaten to veto a debt ceiling hike unless Congress attaches it to the creation of single-payer health insurance.) To weaponize the debt ceiling, you must be willing to inflict harm on millions of innocent people. It is a shockingly powerful self-destruct button built into our very system of government, but only useful for the most ideologically hardened or borderline sociopathic. But it turns out to be the perfect tool for the contemporary GOP: a party large enough to control a chamber of Congress yet too small to win the presidency, and infused with a dangerous, millenarian combination of overheated Randian paranoia and fully justified fear of adverse demographic trends. The only thing that limits the debt ceiling’s potency at the moment is the widespread suspicion that Boehner is too old school, too lacking in the Leninist will to power that fires his newer co-partisans, to actually carry out his threat. (He has suggested as much to some colleagues in private.) Boehner himself is thus the one weak link in the House Republicans’ ability to carry out a kind of rolling coup against the Obama administration. Unfortunately, Boehner’s control of his chamber is tenuous enough that, like the ailing monarch of a crumbling regime, it’s impossible to strike an agreement with him in full security it will be carried out.

The standoff embroiling Washington represents far more than the specifics of the demands on the table, or even the prospect of economic calamity. It is an incipient constitutional crisis. Obama foolishly set the precedent in 2011 that he would let Congress jack him up for a debt-ceiling hike. He now has to crush the practice completely, lest it become ritualized. Obama not only must refuse to trade concessions for a debt-ceiling hike; he has to make it clear that he will endure default before he submits to ransom. To pay a ransom now, even a tiny one, would ensure an endless succession of debt-ceiling ransoms until, eventually, the two sides fail to agree on the correct size of the ransom and default follows.

This is a domestic Cuban Missile Crisis. A single blunder could have unalterable consequences: If Obama buckles his no-ransom stance, the debt-ceiling-hostage genie will be out of the bottle. If Republicans believe he is bluffing, or accept his position but obstinately refuse it, or try to lift the debt ceiling and simply botch the vote count, a second Great Recession could ensue.

When Linz contemplated the sorts of crises endemic to presidential systems, he imagined intractable claims of competing legitimacy—charismatic leaders riding great passionate mobs, insisting they alone represented the will of the people. The present crisis is a variation of that. Republicans insistently point to polls showing disapproval of the Affordable Care Act—a kind of assertion of legitimacy via direct referendum, implicitly rebuking Obama’s counter-argument that the presidential election settled the issue of repealing the Affordable Care Act. But the Republican position rests more heavily on the logic of extortion rather than popular mandate. “No one wants to default, but we are not going to continue to give the president a limitless credit card,” warned Republican representative Jason Chaffetz earlier this year. Obama “will not permit an economic crisis worse than 2008–09,” wrote former Bush administration speechwriter Marc Thiessen, and thus “has no choice but to negotiate with GOP leaders.” Republicans argue that Obama bears all responsibility for avoiding a national catastrophe; Obama argues that both sides bear an equal amount every day—and that this particular mess is not his to clean up.

How to settle this dispute? Here is where Linz’s analysis rings chillingly true: “There is no democratic principle on the basis of which it can be resolved, and the mechanisms the Constitution might provide are likely to prove too complicated and aridly legalistic to be of much force in the eyes of the electorate.” This is a fight with no rules. The power struggle will be resolved as a pure contest of willpower.

In our Founders’ defense, it’s hard to design any political system strong enough to withstand a party as ideologically radical and epistemically closed as the contemporary GOP. (Its proximate casus belli—forestalling the onset of universal health insurance—is alien to every other major conservative party in the industrialized world.) The tea-party insurgents turn out to be right that the Obama era has seen a fundamental challenge to the constitutional order of American government. They were wrong about who was waging it.