In Rendezvous with Destiny, his superb chronicle of Ronald Reagan’s 1980 presidential campaign, Craig Shirley quotes a “remarkably candid” assessment that appeared in The Washington Post eight months before the election. It was written by reporter Lou Cannon, who had covered Reagan’s political career from the outset and seen the candidate from every angle, at his best and his worst. Reagan had gotten plenty of disparaging press coverage, Cannon acknowledged — some of it under Cannon’s own byline. Yet the California governor had never treated him or any other detractor with hostility or rudeness.

“He has, on the contrary, been unfailingly courteous and responsive to his media critics,” Cannon remarked, “never whining about the treatment he has been given or suggesting that the liberties of the press should be curtailed.” Cannon esteemed Reagan’s ability to remain genial and respectful even in the midst of hard-fought, high-stakes political battles. Shirley clearly did too.

Or so I thought until I read “In Defense of Incivility,” a recent essay written by Shirley after hearing Jeb Bush praised because of his appeals for more civility in the race for the White House. Shirley, who has had a long career in conservative activism and public affairs, dismisses civility as “overrated,” a favorite elitist ploy to keep voters quiescent. “The last thing we need in American politics is more civility,” he proclaims. “What we need is more focused anger. … This is Donald Trump’s real contribution to the 2016 presidential contest.”

If civility were a synonym for dispassion and weakness, I might be inclined to agree. If angry smears and strident character attacks were the best way to win debates and advance sound ideas, he might have a point.

But civility is indispensable to the health of a free society, and if anyone should know that, it’s a Reagan-admiring conservative. For as long as I can remember, Republicans and right-leaning libertarians have resented the ad hominem assaults so often hurled against them by their opponents — the defamation of conservatives as “terrorists” and “racists,” the grotesque analogies to Hitler, the automatic assumption of bad faith and evil intent. Lately I have watched with dismay as too many figures on the right have resorted to the same tactics, cranking up the anger and the decibel level, and yielding to the temptation to jeer those they differ from as traitors, haters, and fools.

More incivility? Is that really what American politics needs?

To be sure, politics ain’t beanbag. The United States has never suffered from a shortage of harsh campaign rhetoric. Forceful political combat invariably elicits forceful political arguments, and when citizens wrestle with profound or thorny issues, it is all too easy for intense debate to give way to insults and demonization. Especially when political leaders fan the flames, or when activist groups and opinion-makers warn their followers that any show of civility or compromise is tantamount to a win for the other side.

In politics as in religion, it is important to preach to the converted. But surely it’s as important to preach to the unconverted — to offer a convincing message, to propose a better solution, to open skeptical eyes to a different worldview. That has always been a tough challenge; but it is infinitely tougher in the digital age, when the rawest political venom can go viral overnight, and when media outlets, less restrained than at any time in the past, compete round-the-clock to attract attention and generate “buzz.”

We have reached a point where politicians fear to commit themselves to even the mildest standard of civility. In 2009, two prominent political activists, Republican Mark DeMoss and Democrat Lanny Davis, launched a campaign to try and soften the nation’s harsh public tone. They wrote to all 535 members of Congress and the 50 governors, asking each to sign a simple Civility Pledge: “I will be civil in my public discourse and behavior. I will be respectful of others whether or not I agree with them. I will stand against incivility when I see it.” For months the bipartisan duo promoted their civility campaign. But in the end, of the 585 elected officials to whom they sent the pledge, only three — three — were willing to sign.

We aren’t the first Americans to live in polarized, passionate times, nor the first in which political rhetoric has grown so malignant.

“We must not be enemies,” Abraham Lincoln implored his countrymen in his first inaugural address. “Though passion may have strained, it must not break our bonds of affection.” But Lincoln implored in vain. The bonds of affection did break, and a terrible calamity ensued.

America today may not be on the verge of a civil war. But our ability to find common ground is diminishing by the day, and even those who should know better are calling not for more civility, but less. We are heading in the wrong direction, and it will not end well.

Jeff Jacoby is a columnist for The Boston Globe.