Our divisions are racial and ethnic and class-based and generational, conspicuously so in the Trump era. And they are geographic: The metropolis versus the hinterland, the coasts against the middle of the country. It would not be hard to sketch lines on a map partitioning the U.S.A. into two or three or four more homogeneous and perhaps more functional republics. And if you imagined some catastrophe suddenly dissolving our political order and requiring us to start anew, it is not at all clear that we would be able to forge a reunited republic, a second continental nation.

Moreover, our divisions induce a particular anxiety because each of our two main factions reigns supreme in one particular arena. Conservatism is (somehow) politically dominant, with control of the legislative and executive branches and a remarkable power in the states. Meanwhile liberalism dominates the cultural commanding heights as never before, with not only academia and the media but also late-night television and sportswriting and even young-adult fiction more monolithically and — to conservatives — oppressively progressive.

So both sides have reasons to feel threatened, disempowered and surrounded; both can feel as though they exist under a kind of enemy rule.

Thus described, it may sound remarkable that we haven’t plunged into domestic chaos and civil strife already. But not every American is a partisan, there is still more to life than politics for most of us, and under the right circumstances people with deep differences can live together in peace for a great while — so long as events do not force a crisis, so long as the great political or social questions don’t feel so existential and zero-sum that they cannot be managed or endured.

Slavery was such an existential issue — but its closest analogue today, abortion, does not lie so close to the center of our politics. Race, immigration and religious liberty are all volatile, but the specific controversies are more incremental than existential: Voter-ID laws are not Jim Crow, and toppling Confederate statues isn’t Reconstruction; refugee restrictions aren’t internment camps; fights over the rights of Christian businesses and colleges are not a persecution.

An economic crisis can spur a crackup. But our wealth and the welfare state both cushion us substantially, as we saw after the Great Recession. Wars can lead to dissolution: Opposition to the War of 1812 brought New England to the brink of secession, opposition to Vietnam helped give us our last era of calamity, and of course defeat in World War I broke up the multiethnic empires that the United States increasingly resembles. But our wars are so professionalized and technologized that even unpopular ones can be sustained a long time without pushing domestic politics to a breaking point.

This leaves the most likely near-term threat to our fractured republic as either something external to the system — a worst-case pandemic or terrorist attack, a climate-change-induced catastrophe — or else a threat concentrated at the top, in the imperial presidency around which our democratic derangements increasingly revolve.