For many observers of Colombia, it is hard to imagine that a former member of M-19, the guerrilla group that waged war against the state for nearly two decades, could attain the presidency. Yet in 2022, that is exactly what happened. Gustavo Petro, a former M-19 organizer who later served as a leftist opposition senator and as mayor of the capital city of Bogotá, ascended to the country’s highest office. Petro’s populist platforms and anti-elite discourse clashed with Colombia’s tradition of more centrist, consensual politics, and going into the final round of voting, his victory seemed far from assured. But his promise of far-reaching reforms resonated with Colombians who were tired of the status quo, felt excluded from the country’s economic and political life, and sought greater social justice—so much so that they elected him to be the country’s first leftist president.

Despite Petro’s populist and at times anti-US rhetoric, the Biden administration has since made overtures to the new president, seeking to shore up Washington’s relationship with a country that has long been its chief partner in South America. […]