The Last Word with Lawrence O'Donnell 10/11/17

Fmr. Sen. Maj. Ldr.: 'We're in a dangerous moment in our history'

Lawrence O'Donnell talks to former Senate Majority Leader George Mitchell about President Donald Trump's comment that he wanted to increase the U.S. nuclear arsenal, the future of the Iran deal, and the power of the Senate to restrain Trump. ... more Duration: {{video.duration.momentjs}}