The United States' system of government is a nightmare. The Constitution requires levels of consensus between branches of government that are not realistic in a modern country with ideologically polarized parties. The result is near-total policy stasis and gridlock that in some cases, like the debt ceiling crisis of 2011, risks stopping measures from taking effect that are necessary to prevent total calamity. As the saying goes, things that can't last forever don't, and it's reasonable to predict, as Matthew Yglesias does, that America's untenable system of government will fall apart, probably in our lifetimes.

But Yglesias is vague as to how that will happen. While he's careful to say that past democratic collapses — such as the Honduran constitutional crisis of 2009 — aren't necessarily models for what will happen here, he does seem to presume some kind of crisis. At some point, an impasse between the executive and legislature will create a state of exception, a point at which disaster cannot be averted through normal legal channels.

But it's hard for me to imagine a crisis whose resolution would involve an all-out coup or dissolution of democratic institutions. What's much likelier is a continuation of the executive's gradual consolidation of power until the presidency is something like an elective dictatorship. It won't happen in a big bang, and no individual step in the process will feel like a massive leap into tyranny. But compared to today, the president's powers will be almost unrecognizable.

Why I don't worry about a coup

Yglesias' argument depends a lot on the finding — originally by the late Yale political scientist Juan Linz — that presidential democracies are more prone to collapse than parliamentary ones. There's substantial literature on this question, and it's fair to conclude that the preponderance of evidence suggests that parliamentary systems are more stable. But it's not an uncontroversial proposition, and while I think critics of the theory are wrong, their case nonetheless makes me skeptical of the kind of crisis Yglesias appears to be foreseeing.

University of Illinois's José Antonio Cheibub is probably the most influential defender of presidential systems (or, at least, of their ability to avoid descending into tyranny) within political science. His explanation for why, historically, presidential regimes have been likelier to collapse is that democracies emerging in the wake of military dictatorships are more likely to use presidential systems.

"There is a nexus between military dictatorships and presidentialism that fully accounts for the differences in democratic survival," he writes in his book Presidentialism, Parliamentarism, and Democracy. "Democracies that are preceded by military dictatorships are more unstable than those that are preceded by civilian dictatorships; in turn, presidential democracies are more likely to follow military dictatorships."

Compared to today, the president's powers will be almost unrecognizable

I'm not persuaded that this fully accounts for the difference. As the University of Oregon's William Terry found upon reanalyzing Cheibub's data, presidentialism does appear to contribute to democratic collapse in countries with long histories of democracy (like the US) even if it doesn't in younger democracies.

But Cheibub's theory has one important virtue: it explains how, exactly, democratic collapse happens in presidential democracies — a process that is unlikely to happen here. Any country with a standing army can see its president deposed if the military wants them gone. In countries where civilian control of the military is a strong tradition — like the US — it's hard to imagine that happening.

The obvious counterargument is that civilian-military relations in the US are deteriorating. In a famous 1992 essay, retired Major General Charles Dunlap (then a Lieutenant Colonel) described a hypothetical military coup in 2012. While the rest of government fell in popularity in the 1980s and early 1990s, Dunlap noted the military's popularity grew; as a result, his paper described Congress tasking the military with more and more civilian responsibilities (first law enforcement, then medical care, then education) until it became so powerful that a full-on coup was the logical next step.

But while it's worth worrying that civilian leaders regard military advice with undue deference, Congressional leaders haven't called for the kind of creeping military control at home that Dunlap feared. Moreover, there's no evidence that senior military leadership really cares about the kind of executive-legislative standoffs that threaten the survival of the American system. And there's certainly no indication that military leaders would want to intervene in these power struggles.

How a true crisis will resolve itself

Imagine that a debt-ceiling deal hadn't been reached in the summer of 2011. Imagine that negotiations between Obama and Boehner broke down and no time remained before the debt ceiling was breached.

The stated position of the Obama administration was that this would have triggered default on US treasuries, causing a massive shock to the global financial system and, quite possibly, a new financial crisis. While many — including former President Bill Clinton and a number of Democrats in Congress — urged Obama to invoke the Fourteenth Amendment and judge the debt ceiling unconstitutional, the president stated that his legal advisers were "not persuaded that that is a winning argument." At the time, he didn't address the idea of minting a trillion-dollar coin and using it to buy up debt from the Federal Reserve, though in 2013 the administration ruled it out. Not reaching a deal, the administration insisted, would be catastrophic.

Insisting on the imminence of disaster is a great bargaining maneuver, but there is no way in hell the administration was serious about letting the government hit the debt ceiling. Failing to invoke the Fourteenth Amendment or mint the coin would have been a moral obscenity, causing needless suffering to befall millions of people, all because the president let his need to color inside the lines overwhelm his ethic of responsibility to his citizens.

Obama knew this. He had to know this. That's why Obama's lawyers considered the Fourteenth Amendment option, and Obama was careful to not rule it out unconditionally. It's why the Justice Department's Office of Legal Counsel drew up a memo on the trillion-dollar coin option. They knew that, if push came to shove, they had to have a way out, even if it was a little legally murky.

Obama would have shredded the debt ceiling. Republicans would have said it was an unprecedented executive power grab, and Democrats would have told them to calm down, it's not that bad. They're both right: Obama would have been claiming new powers, but that wouldn't have involved some kind of epic descent into tyranny.

This is why I'm skeptical of the crisis story for American democratic collapse. Breaching the debt ceiling is just about the worst thing that can happen in the American government in the absence of a major war or depression — and even it can be prevented without resorting to a full-on power grab by the president. It's not the only kind of crisis we face, but the other types provide even less motivation for a suspension of democracy. Government shutdowns are bad but, as 2013 reminded us, not that bad. They work well as political battlegrounds precisely because politicians can threaten to provoke them and actually follow through without causing massive damage.

States of emergency

The most likely scenarios for a dramatic presidential seizure of power, then, are economic collapses and national security emergencies. While it's theoretically possible that Congress could deny war funding to a president after a major foreign power attacks the US, it's hard to imagine any Congressional opposition party being that politically stupid.

That leaves economic emergencies. This is the one I come closest to worrying about. There were real calls in 1933 for Franklin Roosevelt to seize dictatorial powers in order to deal with the Great Depression. Nationally syndicated columnist Walter Lippmann wrote, "A mild species of dictatorship will help us over the roughest spots in the road ahead." The New York Herald-Tribune's Inauguration Day issue featured the headline, "For Dictatorship If Necessary." There's some evidence Roosevelt himself considered this; his wife Eleanor privately expressed support for him becoming a "benevolent dictator."

But Roosevelt declined, and there's reason to think the impulse to turn toward dictatorship won't return in future downturns. For one thing, economic collapses tend to lead to massive gains by one political party: think Democrats' takeovers in 1932 and 2008. That defuses executive-legislative tension and makes responding to the crisis easier, thereby obviating the need for the president to exercise extraordinary powers. Moreover, Roosevelt came to power as fascist Italy was gaining respect from American commentators and dictatorship was ideologically in vogue, which is a hard intellectual trend to imagine reemerging.

What I think will happen

Assuming we won't have a world war or second Great Depression in the next few decades, we'll be confined to normal, run-of-the mill crises. Those aren't the problem. The risk is that congressional gridlock — which will only worsen as parties polarize on ideological lines — will make major revisions to statutes and changes in the fiscal status quo next to impossible.

Any president worth his salt is going to want to make major revisions to statutes and to alter the fiscal status quo. They're going to want to raise taxes on the rich and increase transfer programs, or slash taxes across the board while restructuring entitlement programs, or rewrite No Child Left Behind and make Medicare more cost-effective, and so on. Their legacy as more than placeholders depends on leaving some kind of legislative mark.

So they're going to gradually start using executive powers to adjust policy in those domains. President Obama has been very open about this. He couldn't get the Waxman-Markey cap and trade bill through the Senate, so he had the EPA impose carbon emissions regulations instead. He couldn't pass the DREAM Act, so he used executive authority to protect DREAMers instead. He couldn't get Congress to adjust No Child Left Behind, so the Department of Education started using waivers to do that in effect.

Some of these actions are on firmer legal precedent than others (the EPA rules are entirely legitimate, the No Child Left Behind waivers are more questionable) but the pattern is unmistakable. President Bush, of course, pushed the limits of executive authority too. The NSA wiretapping program began with a secret executive order long before Congress formally authorized it, and Bush made prolific use of "signing statements" asserting he had, in the words of the New York Times, "the power to set aside any statute passed by Congress when it conflicts with his interpretation of the Constitution."

I'd guess that the Congress of 2050 will largely serve to ratify decisions the president made unilaterally

My prediction is that this process will continue apace until the presidency's powers are so immense as to be no longer recognizable. Norms that render dramatic actions impossible today will erode. Right now, it'd cause an uproar if a Republican president issued a blanket pardon for tax offenders who paid only what they'd owe if his tax plan had taken effect. But as changing tax policy through Congress becomes harder, that norm will weaken and an executive action like that will become plausible.

Courts can try to block these actions, but an increasingly partisan judiciary could serve to defend presidents against that. Barring that, simply ignoring court rulings (as the Bush administration did when the Supreme Court ruled it had to regulate greenhouse gases) could become more common.

There are limits to how far this can go, of course. It's hard to imagine an executive action creating a tax increase, or criminalizing a currently legal activity, or increasing spending levels. Even there, though, the president's increased powers will in turn increase his leverage with Congress and make it easier for him to demand the few legislative changes he can't effect on his own. Think of how easily the presidency steamrolls Congress on most foreign policy matters, a domain where it already has near-dictatorial powers. Congress's maximum influence is piddling, so it has little reason to assert itself.

This won't be a fast process. But if I had to guess, I'd say that the Congress of 2050 will largely serve to ratify policy decisions the president made unilaterally.

The best-case scenario is that we wind up with an elective dictator but retain peaceful transitions of power. This is where I'd place my bet. Pure parliamentary systems, especially unicameral ones, give high levels of power to the prime minister and his cabinet, and manage to have peaceful transitions nonetheless. The same is true in Brazil, where the presidency is considerably more powerful than it is in the US.

But parliamentary systems also feature parties that are stronger than their leaders, which serve to prevent single individuals from garnering too much power. America's parties are getting more polarized, but they still aren't as strong as those of most other developed nations.

The worst-case scenario is if the presidency attains these powers and someone elected to the office decides to use them to punish political enemies, interfere with elections, suppress dissent, and so forth. Retaining an independent enough judiciary is a guard against this, but only if norms around obeying its rulings are strong. And, unusually, America allows for true independents, undisciplined by their parties, to become heads of government.

I don't think a full-on evolution into dictatorship is an especially likely outcome. But the fact that the concentration of executive power makes it possible gives me pause — and should make us all consider peacefully replacing our current system with one less likely to fail us.