To mark National Voter Registration Day, directors Lisa Cortés and Liz Garbus talk about the new Amazon Studios documentary “All In: The Fight for Democracy,” which traces the history of voter suppression efforts in America from the earliest days of the republic. The film looks particularly at the 2018 Georgia gubernatorial race, in which Brian Kemp narrowly beat Stacey Abrams, and the impact that voter suppression can have on election outcomes.