It's unlikely that the government will shut down next week. It's certainly possible, of course; Congress' track record on beating important deadlines of late is mixed. And we'd note that a week before the shutdown in 2013, most people probably figured it would be avoided.

So it's unlikely, but it could happen. Fine.

The prospect, though, made us wonder: What if it does -- or what if it does at some point in the not-distant future -- and the government doesn't reopen? What if Congress can't reach a deal on a budget, and then can't figure out how to extract itself from the situation?

What if the government shut down forever?

There are a million reasons this is unlikely. For one, the effects of a long-term shutdown would be so politically toxic that some majority of Congress would certainly agree to reopen the government. For another, a long-term/everlasting shutdown would essentially dismantle the United States. But it's interesting to consider what lies along that path, and where it leads.

A shutdown is a budget issue. The government stops performing its usual functions because it (theoretically) can't be certain that it can pay for what it's doing. In 2013, the government shut down for just more than two weeks as Republicans stood behind a federal budget that excluded funding for Obamacare, which Democrats insisted be included. Everyone in the room knew that the shutdown would end at some point; within a matter of a few days the issue became about saving political face as much as resolving the core dispute. Employees were promised that they'd be paid for time worked after the shutdown was over. Most government functions kept marching forward, while things like parks and monuments were sort of half-heartedly shuttered.

Which Julian Zelizer, political historian at Princeton University, thinks provided a murky picture of the damage a shutdown could do. "The last round made it plausible that a short-term shutdown is something you could live through. It's not a disaster," he said. "So I imagine that this is going to continue to be something that we continue to see." The normalization of shutdowns and the limited negative effects on the public, in other words, may mean more, longer shutdowns in future. And that's when bad things might happen.

So let's say the government shuts down next week. At first, the same promises would be made: Social Security checks will go out, the military will stay on guard, employees working to make those things happen will get back pay. Now let's say that we pass the two-week mark, and the four-week mark, and the shutdown starts being counted in months. There are two problems: 1) The government needs to actually start shutting things down in a significant way, and 2) it needs to borrow more money from increasingly skeptical lenders.

"It's hard, because almost every program I can think of is something that people want. That's the great puzzle of American politics: People hate government but depend on it and like it when you talk about specifics," Zelizer said. "I don't know what you'd cut because every cut would be politically unpopular."

Among the first to be cut would be programs with weaker political support. We are talking about the decisions being made by actors in a political world, after all.

So what goes first? "Programs for vulnerable people. The food stamp program. Child care. Infant care. These are important programs but they are vulnerable because their constituencies are not constituents with a whole lot of political power," Zelizer said.

Next in line, regulatory agencies. Occupational Health and Safety Administration (OSHA) or the EPA or financial regulators would likely see their budgets slashed. There are political benefactors for these things, but compared to other budget priorities, it's easy to see why they'd be cut quickly. Also cut early, per Zelizer: Visa and passport issuance, arts programs, scientific research. The things, in other words, that affect the smallest and least-vocal and -powerful groups of people — or affect the powerful and vocal in only minor ways.

At this point, it's safe to assume that financial markets would be freaked out. The government has a significant role in the national economy. "You could see a huge swing in the stock market. ... Federal contracts would dry up, which means that ... cities and suburbs and rural communities across the country that depend on the government would not have the money they were expecting." It would affect the housing market, as loans from the federal government stop. The closure of parks and museums, a battleground in 2013, would mean sharply reduced revenue in places that depend on tourist money.

For those things that the government can't shut down, it would need to take out loans. Imagine that person, sitting in a dark office in the Department of the Treasury, unsure if she'll be paid any time soon, trying her best to twist arms and keep money flowing in. Interest rates would spike as time passed, with creditors increasingly nervous that they'd ever be repaid — and exacting a high cost for offering that trust. Incoming tax revenue is never enough to pay our bills by itself; it wouldn't be in this scenario, either. And that's assuming people actually kept paying their taxes, which, over time, might be less and less the case.

If the shutdown continued, it's hard to predict the order in which services would go dark. But Zelizer offered his opinion on which things would be maintained until the end.

"Theoretically, Social Security would continue because it's funded on its own," he said, and "that's a big part of what government does." Air traffic control. Emergency response, in the event of a natural disaster. "They'd find the revenue to do something. They're not going to allow the kinds of things you see in a Hollywood movie to occur."

National security would be near last on the list — as would federal prisons and border control. "The government is not going to shut those down unless there's a scenario where we've hit rock bottom." We wouldn't want prisoners released into the public or the borders opened entirely — though people might be emigrating more than immigrating by that point.

By this point, American society as we know it would have already shifted substantially. It's hard to imagine Congress wouldn't have acted, or, as Zelizer points out, some external factor (like a coup) would have come into play.

Jack Rakove, professor of American studies at Stanford University, figures that the country would essentially have reverted to the time of the Articles of Confederation. "This would become the 21st century of the 'Critical Period,' " he said, referring to the period just before the adoption of the Constitution. "The operative word used to describe the state of the national government at the time was that it was moving to the condition of imbecility."

Asked what that would look like, he was blunt. The federal government would "not look like anything" if a permanent shutdown kicked in, Rakove said. Instead: "You can imagine a radical devolution of authority to the states."

That would not necessarily be the paradise that strong states-rights advocates might imagine. "We remain a nation where lots of aspects of government remain truly national," Rakove said. "It would be hard for Idaho to build a new effective, four-lane superhighway system from Coeur D'Alene to Pocatello."

Not to mention that the national government helps shift funding to the places that need it the most. Wealthier states pay more in taxes than they receive in government services, and vice-versa. States like Alabama or New Mexico — or, yes, Idaho — get more from the federal government than they pay out. That trade-off would collapse, at least formally. (And depending on how we got into this situation, wealthier states might be leery about aiding their neighbors.)

In short, we'd probably just need to start over. Rakove, a historian, pointed to the Federalist Papers, the initial debate over how a united nation should be composed. In Federalist 37, James Madison writes about the difficulty of crafting the original Constitution.

"The history of almost all the great councils and consultations held among mankind for reconciling their discordant opinions, assuaging their mutual jealousies, and adjusting their respective interests," he wrote, "is a history of factions, contentions, and disappointments, and may be classed among the most dark and degraded pictures which display the infirmities and depravities of the human character." That's the battle that the creators of the New United States would face -- even after having just fallen victim to precisely that tumult.

Rakove did, however, find one silver lining in the everlasting-shutdown scenario: "It would make work for future historians."