For the first time in its history, Colombia has elected a leftist president. Gustavo Petro is a former guerrilla who became mayor of Bogota and then a senator. He defeated right-wing populist Rodolfo Hernández. As Nick Schifrin reports, his election overturns the center-right political establishment that has long run Colombia, and it could usher in a dramatic change with its U.S. relationship. Stream your PBS favorites with the PBS app: https://to.pbs.org/2Jb8twG Find more from PBS NewsHour at https://www.pbs.org/newshour Subscribe to our YouTube channel: https://bit.ly/2HfsCD6 Follow us: Facebook: http://www.pbs.org/newshour Twitter: http://www.twitter.com/newshour Instagram: http://www.instagram.com/newshour Subscribe: PBS NewsHour podcasts: https://www.pbs.org/newshour/podcasts Newsletters: https://www.pbs.org/newshour/subscribe