What can Ukraine's elections tell us about Russian interference? "There’s nothing that Russia will do to the U.S. that it won’t do to Ukraine first and worst," Jigsaw CEO Jared Cohen says. From his interview on GPS: | Fareed Zakaria

Prof. Robert Sapolsky explains how neuroscience explains nationalism--and how our brains are wired to differentiate between "us" and "them." Our full GPS interview below. This Sunday, at 10 a.m. and 1 p.m. ET on CNN, we'll discuss the New Zealand attacks, Venezuela, and Brexit with Anne-Marie Slaughter, David Miliband, and Ian Bremmer; hear from Sanjay Gupta about his new HBO documentary, "One Nation Under Stress"; talk with Jigsaw CEO Jared Cohen about the upcoming Ukraine elections and Russian