Here is the core American question. As we continue our own “big sort,” will the desire to separate trump the desire to dominate? Or can we instead choose to tolerate? We’re still quite far from the kind of near-miss that Britain just experienced, and we’re even farther removed from the vicious strife of a true civil war, but the trends are pointing toward continued matching of like with like — and along with that, increasing hostility against communities not like our own. In my Memorial Day column, I asked what I believe to be the key question: “Is there a single significant cultural, political, social, or religious trend that is pulling Americans together more than it is pushing us apart?”

I don’t believe a civil-war mentality will save America. There are simply too many differences and too many profound disagreements for one side or the other to exercise true political dominance. Red won’t beat blue in the same way that blue beat gray. Adopt the civil-war mentality and you’ll only hasten a potential divorce. No, absent a presently unforeseen unifying ideology, event, or person, the idea that will save America is one of the oldest ideas of the Republic: federalism.

So long as we protect the “privileges and immunities” of American citizenship, including all of the liberties enumerated in the Bill of Rights, let California be California and Texas be Texas. De-escalate national politics. Ideas that work in Massachusetts shouldn’t be crammed down the throats of culturally different Tennesseans. Indeed, as our sorting continues, our ability to persuade diminishes. (After all, how can we understand communities we don’t encounter?)

If we seek to preserve our union, we’re left with a choice — try to dominate or learn to tolerate?