Colombia now has its first leftwing president: Gustavo Petro. He’s a [deep breath] sixty-two-year-old-ex-leftist-guerilla-turned-mayor-turned-opposition-leader who rode a wave of voter anger to a narrow victory over a populist construction magnate last June. Got that?

Petro was swept to power by a slim margin in June, thanks mainly to young Colombians. He had promised them something different in a country that's been rocked by mass protests over inequality and corruption, Ian Bremmer explains on GZERO World.

Colombia's new president, who started his political career as a leftist guerrilla in the 1990s, promises change. He wants to fight climate change by ending oil exploration and to massively increase social spending by taxing the rich more.