Teresa Bejan is a professor of politics at the University of Oxford and the author of "Mere Civility: Disagreement and the Limits of Toleration."

Credit: Eugene and Louise for The Washington Post

In our divided nation, it seems civility has gone out of fashion. In his inaugural address, President Trump called for Americans to prioritize openness, honesty and the need to “speak our minds.” At the time, the president’s demotion of the theme of civility (rhetorically central to both of his predecessors) shocked no one. More surprising, perhaps, is the speed at which partisans on both sides — including some of his fiercest critics — have taken his advice to heart. As Democrats settle in for a long winter in the opposition, President Barack Obama’s high-minded encomia to conversational virtue have been replaced by calls for conscientious incivility as a sign of resistance to the new regime.

Confronted with an amateur politician determined to bring his distinctive brand of Twitter-based ad hominem to the White House, what’s a member of the opposition to do? For some on the left, an extension or even escalation of the war of words characteristic of a bitter campaign season seems like a reasonable response. When the president attacks a member of the judiciary as a “so-called judge” or wishes Happy New Year to his “many enemies, ” civility appears, at best, a loser’s game. At worst, going high at each new low is a moral mistake that will only serve to normalize the status quo. Now, supposedly, is the time to call a spade a spade — or a “fascist,” as the case demands. A troubled observer might note that the distance between successfully labeling someone a fascist or a white supremacist and legitimizing the use of force to silence his uncivil speech is short, indeed. Even the New York Times has suggested that it may be okay to punch a Nazi.

As our wars of words threaten to give way to swords, the historically minded may detect an uncanny echo of another, early modern crisis of civility. 500 years ago when Martin Luther posted his “95 Theses” to the door of a church in Wittenberg, Germany, he not only launched the Protestant Reformation, he also inspired generations of conscientiously uncivil evangelical Christians and a surfeit of sectarian polemic that shattered the unity and concord of Western Christendom for good. Like Trump, Luther was a virtuoso of insult who took full advantage of new communications technologies (in this case, the printing press) to popularize his message and cut his more established opponents down to size.  Both friends and foes followed suit. When Luther dubbed the pope the “Antichrist” and Catholics “anti-Christians,” the labels stuck for centuries. And when the pope responded by anathematizing Luther as a heretic, he also (literally) “denominated” Martin’s followers “Lutherans” so that they might share in his punishment and shame.

Then as now, many observers blamed the epidemic of incivility for the violence that followed. The philosopher John Locke noted that the “disgraceful appellations” with which sectarians on all sides demonized their opponents had the same dehumanizing effect as the animal skins the Romans had used to cloak Christians before feeding them to lions. Accordingly, authorities across Europe and the Americas tried to crack down on religious controversy by banning insulting denominations like “Huguenots,” “Papists,” “Baptists” and “Puritans” in the name of social harmony.

Yet the prosecution of incivility was often a convenient pretext for persecution: Atheists were accused of indifference to the “offensiveness” of their discourse for believers, while in England, adverbial definitions of heresy — for example, as an erroneous opinion “obstinately” or “factiously” adhered to — fell disproportionately on unpopular minorities such as Anabaptists and Quakers. In these cases, complaints about the manner of disagreement quickly reduced to the substance, and laws meant to protect dissenters from insult became a much more effective means of shutting them up. One Puritan preacher, Thomas Watson, complained that self-styled “civil persons” were usually motivated by “a secret antipathy against the ways of God.”

Today, similar suspicions abound on both sides of the aisle. For a virtue aimed ostensibly at facilitating disagreement, civility more often functions to shut down dissent, as in the recent silencing of Elizabeth Warren on the Senate floor. That case illustrated how accusations of incivility function to place the accused beyond the pale of reasonable or respectable debate. Indeed, the phrase “beyond the pale” — which originated in the early modern period as a reference to the geographical “Pale” (from the Latin word for “stake” or “fence”) around Dublin meant to separate the “civilized” Anglo-Protestants from the “barbarous” Irish Catholics beyond — is indicative of the problem. It suggests that Republicans were on to something during the Obama years when they accused Democrats of using claims of incivility to sidestep argument and score political points. While the dangers of political correctness cited by some Trump supporters may be overblown, there is no doubt that the president derives much of his power as an avatar for the wide swath of the electorate that continues to feel silenced and stigmatized as “deplorables” by their self-styled betters, hence beyond the progressive pale.

Still, if history confirms how easily calls for civil disagreement can justify suppression and exclusion, it also demonstrates how essential civility is in navigating heated disagreement — albeit civility of a particular and peculiar kind.

Here, modern Americans could stand to learn a thing or two from the 17th-century founder of Rhode Island, Roger Williams. Far from being a proto-multiculturalist, Williams was exiled from Massachusetts because his theological intolerance and evangelical zeal made even his fellow Puritans uncomfortable. He knew firsthand how accusations of incivility could be used to persecute, suppress and exclude. Nevertheless, in Rhode Island, he took up the banner of civility and in so doing created the most tolerant and inclusive society the world had ever seen.

The key to this apparent paradox was Williams’s commitment to what I call mere civility. As the minimal, often grudging conformity to social norms of respectful behavior needed to keep a conversation going, this civility falls far short of the reasonableness and mutual respect its proponents usually have in mind. Williams knew from experience that the “bond of civility ” necessary to hold a tolerant society together was less a matter of avoiding insult than cultivating the mental toughness to tolerate what we perceive as our opponents’ incivility, to live with them and continue to engage, even when we think them irredeemable. “As if because briars, thorns, and thistles may not be in the garden of the church,” wrote Williams, “therefore they must all be plucked up out of the wilderness. Whereas he that is a briar, that is, a Jew, a Turk, a pagan, an anti-Christian, today, may be (when the word of the Lord runs freely) a member of Jesus Christ tomorrow.” Accordingly, Rhode Island welcomed Catholic “anti-Christians,” as well as Jews, Muslims, American “pagans” and Protestants of all stripes. Williams was pretty sure they were all going to hell and told them so; still, he thought one must “go out of the world” entirely to avoid keeping company with such “idolators.”

As practiced by Williams, mere civility was more often an expression of mutual contempt than mutual admiration. We might recognize it as the virtue governing those unpleasant-but-unavoidable interactions with ex-spouses and bad neighbors, as well as anyone who voted for the other gal (or guy). But even mere civility can be quite demanding: In attempting to understand other minds on the model of our own, people make sense of disagreement by concluding that our opponents are stupid, bigoted, evil or even insane. Yet mere civility demands that we keep the disagreement going, no matter how disagreeable, to continue the battle of words without resorting to violence. Judging by the criteria of mere civility, Trump’s worst infractions rest less on his Lutheran talent for insult than on his record of using his wealth and position to bully his critics. As victims of civil silencing themselves, his supporters must speak out against these efforts and defend the right to free and frank speech for their opponents as well.

As American politics comes to resemble the self-righteous sectarianism of the Reformation more and more every day, the temptation on all sides to give up on civility is understandable: Calls for civility can serve as swords as well as shields, and they are often abused to put an end to disagreement rather than enable it. Nevertheless, rejecting the idea of civility altogether would be a serious mistake, because abandoning our co-citizens in favor of the more agreeable company of the like-minded is what got us into this mess in the first place. If we are to break the self-perpetuating cycle of epistemic closure, complacency and self-congratulation, we must embrace Williams’s mere civility as a commitment to using our words with, as well as against, our opponents. To live together, we must be able to talk to one another; the fate our own tolerant society hangs in the balance.