Gustavo Petro: Colombia’s next president?

After a solid display in Colombia’s congressional race and a landslide win in his coalition’s internal consultation, pollsters now have Gustavo Petro in pole position to become the first left-wing president in the country’s history. 

With almost five decades in politics, despite being just 61 years of age, Mr. Petro witnessed firsthand how violence during the Cold War era made Colombia one of the most dangerous places on Earth in which to participate in public affairs.

As a member of the armed left, he was a protagonist in multiple landmark moments in the country’s contemporary history, from the demobilization of guerillas to the drafting of the Constitution.

Now, he could put an end to 25 years of right-wing dominance – in a country that has so far been the clearest exception to the so-called “pink tide” in Latin America.

The years of violence

Mr. Petro was imbued with politics from a young age. As a child in the 1960s, his mother recounted stories about Eliécer Gaitán, the popular leftist leader killed in 1948, whose death sparked the Bogotazo protests and then the proto civil war known as La Violencia.

These were the days of the Frente Nacional in Colombia, an alliance between the country’s two traditional parties, Liberals and Conservatives, which saw them sharing power and rotating the presidency while marginalizing other groups.

The main critic of that duopoly was General Gustavo Rojas Pinilla, a popular dissident conservative that imitated Argentina’s Juan Domingo Perón, during his military interregnum in the 1950s.

Mr. Pinilla built a growing alliance with the left, and on the night of the 1970 election, official results had him as the unexpected winner against the Liberal-Conservative pact. But by the next morning, his narrow victory had turned into a narrow defeat, amid multiple accusations of fraud in distant regions. Political disenfranchisement paved the...