I want to turn your attention to this subject: ‘Loving Your Enemies.’  I have recently written a book on that theme, but the words are found in a sermon by the Rev. Martin Luther King Jr., delivered in Montgomery, Ala., on Nov. 17, 1957. King was referencing the teaching of Jesus in Matthew’s Gospel and exhorting the congregants to live that teaching in their everyday lives.

Noble stuff, you’re probably thinking — so idealistic. But unrealistic and, frankly, impractical. And not just in situations of warfare and violence; in modern American politics, too, where we are as far apart ideologically as we have been at any time since the Civil War. You either show up ready to fight, or you lose, because the other side is playing for keeps, right?

Actually, you’ve got it all wrong, according to King. In his sermon, he demolished the argument that Jesus’ teaching is somehow unworkable in our ideological battles. “Far from being an impractical idealist,” he said, “Jesus has become the practical realist.”

Why? If you have strong political views, ask yourself what your objective is in interacting with those on the other side. Is it to exile or harm the other person? Almost certainly not. On the contrary, your goal is to make them think differently. So ask yourself: How well is hate working to meet that goal? “If you hate your enemies,” King taught, “you have no way to redeem and to transform your enemies.”

No one has ever been insulted into agreement. Even worse, contempt toward your foes creates what psychologists call the boomerang effect: If you insult someone with whom you disagree, the odds are greater than 3 to 1 that the person will harden his views against your position. Hate is self-defeating.

That is the case I have been making in speeches across the country. There has been plenty of resistance to the message. A typical counterargument will insist that some people are simply beyond the pale, their ideas so intolerable that responding with hatred is the only option. Who is this enemy? Pretty ordinary Americans, oftentimes, but ones who hold strongly differing views. I hear them compared to Stalinists and Nazis.

That attitude is both wrong and dangerously radical. Anyone who can’t tell the difference between an ordinary Bernie Sanders supporter and a Stalinist revolutionary, or between President Trump’s average voter and a Nazi, is either willfully ignorant or needs to get out of the house more. Today, public discourse is shockingly hyperbolic in ascribing historically murderous ideologies to the tens of millions of ordinary Americans on the other side of a political argument.

Such contempt is based on a mistaken assumption: that there is no room for common ground, so there is no reason not to polarize with insults. That is almost always incorrect. An example that always amazes comes from a now-famous video shot in 2017 on the Mall in Washington, in which Hawk Newsome, president of Black Lives Matter of Greater New York, found himself thrust onstage at a Trump rally. Within two minutes, he turned boos into cheers by describing how his activism was based on love for America.

Fine, you’re probably thinking, but what about the odd people out there who really are Stalinists and Nazis? There are people at the absolute fringes who propagate conspiracy theories, hate and racism — who in normal times would be dismissed as the tinfoil-hat crowd but, in the current hateful environment, capture public attention. Some do it under their own names; others are anonymous. What do we do about them?

Let’s start with anonymous hate. I get my share of it, especially on social media. My view is that you should never be anonymous or engage with anonymous interlocutors. Engagement with love is a human endeavor, requiring us to deal with other people — not with disembodied messages. And the people who say hateful things openly, with views that are truly worthy of contempt? Remember that their views might be, but that noperson is. Repudiate their views, confidently and concisely, but with respect.

If you still object to my argument, you may think I am urging you to find a way to agree with your enemy. That isn’t it. Disagreement — even nonviolent protest, as King showed — is a good thing. It is the essence of the competition of ideas that brings progress and excellence. Love and agreement are not necessarily complementary, or even desirable. If your opponent makes a good point, by all means have the humility to be persuaded, but only if warranted by the facts and your morals.

Nor am I arguing that you must like your enemy. Speaking of Jesus, King said in his sermon: “It’s significant that he does not say, ‘Like your enemy.’ Like is a sentimental something, an affectionate something. There are a lot of people that I find it difficult to like.” You can act out of love — by which I mean to will the good of another — without feeling warm affection.

My Harvard colleague Danielle Allen, a political theorist, has persuasively argued to me that this is more or less what Aristotle meant when he exhorted people to exhibit “politike philia ” — political friendship.