Lift for the left.

THE narrow victory of Gustavo Petro in last Sunday's run-off election constitutes a landmark event for Latin America's third most populous nation. Whether it will also qualify as a Colombian watershed remains to be seen.

Colombia for the past 200 years has veered between the right and the far right, which might help to explain why left-wing elements sought to redress the imbalance via guerrilla movements and insurrections.

It didn't work out, and the response of the state - America's closest ally in the region - frequently tended towards overkill involving death squads. There is an extended history of extrajudicial killings - known locally as the 'false positives scandal', similar to the subcontinent's litany of 'fake encounters' - that continues to be illuminated by court hearings and a special tribunal.

It took until 2016 for the largest guerrilla group, the Revolutionary Armed Forces of Colombia, to enter a peace process. But M-19, the mainly urban group that Petro joined as a teenager, abandoned violence as far back as 1990. Petro subsequently served as a senator and as the mayor of Bogota, Colombia's capital.

Colombia's election result may be a watershed.

His presidential aspirations were nonetheless knocked back twice, and it wasn't implausible to assume when he entered this year's race that Petro would be unlucky a third time. But the popular mood in Colombia has changed since he was defeated in 2018 by the incumbent, Ivan Duque.

Dozens of deaths in the security state's response to protests that broke out a year ago no doubt helped to shift that mood. Beyond that, there's a dynamic pretty much across the western hemisphere where younger generations - not unanimously by any means, but in large numbers - are looking left for answers to the sordid inadequacy of the status quo.

They are regularly being thwarted in 'developed' democracies, such as Britain and the US, where the likes of Jeremy Corbyn and Bernie Sanders have been sidelined by vested interests. Latin America has been a different story for the past couple of decades, though.

The first 'pink tide' presaged by the emergence of Hugo Chavez as Venezuela's president at the turn of the millennium seemed a few years later to have been a false start in some ways. It was swept back to some extent by a right-wing resurgence - on a continent where the US had long informally decreed that only political conservatism could replace neo-fascist military rule.

Latin American populations had...