Last week I interviewed Colombian President Iván Duque, who took office in August and calls himself a man of the “extreme center.” In an era of rising populism, I asked, how should politicians make the case for reviving or strengthening centrist-style politics?“When you see a populist,” Duque answered, “you always see a demagogue. Societies no longer need demagogues; they need pedagogues — people that can tell a country, ‘Where is it that we want to go, how is it that we want to make it happen, and what is it that everybody has to put in the basket to achieve those goals?’ ”Colombians have something to teach the rest of us about the need to preserve a vital political center. Long before cocaine wars and guerrilla insurgencies nearly destroyed Colombia in the 1980s and ’90s, some 200,000 people perished in a civil war in the 1940s through the ’60s because the country’s liberals and conservatives couldn’t settle their ideological differences peacefully.Politics played as blood sport degrades personal manners and ruins civic institutions. That’s where we are in the United States today. Left unchecked, it blows up countries. Colombians know, because it has taken them three generations to work their way out of the wreckage, and they’re far from done.Colombians also know something about demagogic populism, having seen its effects play out in neighboring Venezuela since Hugo Chávez began his “Bolivarian Revolution” nearly 20 years ago. Today, Colombia is bearing the brunt of the worst refugee crisis in recent Latin American history, as close to one million Venezuelans have poured across the border in less than two years, seeking relief from widespread starvation and the violent authoritarianism of Chávez successor Nicolás Maduro. This is the same Bolivarian Revolution that was enthusiastically embraced by Jeremy Corbyn, Naomi Klein, Michael Moore, Oliver Stone, Cornel West and other comfortable tribunes for democratic socialism in the West. Anyone who thinks that left-wing populism is the appropriate remedy for the right-wing variety should look at Venezuela — where the health care is universal and, thanks to socialist shortages, there’s none of it. Colombia’s effort to steer clear of both should be an inspiration. The refugee crisis has put immense pressure on its vulnerable economy. But Duque has refused to scapegoat the migrants or turn his back on them. “We will never close our borders,” he says, “because we want to build this fraternity and because we know that this is a bigger challenge.”What a difference between Duque’s approach and the “build the wall and imprison the kids” crowd currently in power in Washington, Budapest, Rome and other right-wing redoubts. What a difference, too, with the simplistic humanitarianism of Angela Merkel, whose “let them in” approach to the Syrian refugee crisis accounts for much of the anti-immigrant backlash and was never paired with a serious attempt to end the crisis at its Syrian source. Instead, Duque is calling forthrightly for maximum pressure on Caracas, with a clear view toward ending Maduro’s rule. He disavows military solutions “because that is what the dictator wants.” But he’s fairly explicit in calling on Venezuelans to take matters in their own hands, and even more so in applying crushing sanctions on the regime.“Martin Luther King used to say that silence can turn you into an accomplice,” he says. “The stage where we are right now is the stage where we can no longer be indifferent. The whole international community must react.”Duque has also not been silent about the failings of Colombia’s vaunted peace deal with the Marxist rebels of the FARC — the deal that delivered the 2016 Nobel Peace Prize to Duque’s predecessor, Juan Manuel Santos, even as it was rejected by Colombians in a referendum. Last month, The Times reported that rebels are once again taking up arms while their leaders again take up drug trafficking. Those of us who are skeptics of peace deals with terrorists would say: “Told you so.” Duque is committed to keeping but amending the accords. But he complains about the way in which the word “peace” was manipulated by his predecessor into a partisan wedge issue by treating opponents of the agreement as “enemies of peace.”In the age of Trump, it’s easy to forget that elitism and demagoguery can also mix with noxious results. Anyone tagged a “warmonger” simply because they thought the Iran deal was badly negotiated knows the feeling.We are now at a moment when populist demagogues of right or left have won or made major gains in nearly every important recent election: in Pakistan and Mexico; Italy and Sweden; the U.K. and the U.S. It might yet happen again this month in Brazil.To debate the overarching causes is somewhat useless. Unhappy families, to borrow Tolstoy’s line, are unhappy in their own way. Then again, happy families are alike, and so are countries. Reclaiming the extreme center is the way it’s done, and Colombia has lessons worth learning.Follow The New York Times Opinion section on Facebook and Twitter (@NYTopinion), join the Facebook political discussion group, Voting While Female, and sign up for the Opinion Today newsletter.