Filmmaker Michael Kirk joins us to discuss his latest PBS Frontline documentary “Bannon’s War.” Kirk profiles Trump's controversial advisor Steve Bannon. Bannon gained a following working with the alt-right website Brietbart, and developed over time a nationalist message that would propel Trump to the presidency. The film explores Bannon's ideology, his time working on the Trump campaign and his power struggles inside the White House. "Bannon's War" premieres on May 23 at 10 p.m. on WNET.