Former Homeland Security head's advice following Capitol attack: "Buckle up"

Former Homeland Security Secretary Michael Chertoff talks with CBS News national security correspondent David Martin about the failure of the Capitol Police to prevent armed Trump supporters from breaching a Joint Session of Congress, despite threats of violence posted on social media in the runup to the Electoral College vote tabulation. Subscribe to the "CBS Sunday Morning" Channel HERE: http://bit.ly/20gXwJT Get more of "CBS Sunday Morning" HERE: http://cbsn.ws/1PlMmAz Follow "CBS Sunday Morning" on Instagram HERE: http://bit.ly/23XunIh Like "CBS Sunday Morning" on Facebook HERE: https://www.facebook.com/CBSSundayMorning/ Follow "CBS Sunday Morning" on Twitter HERE: http://bit.ly/1RquoQb Get the latest news and best in original reporting from CBS News delivered to your inbox. Subscribe to newsletters HERE: http://cbsn.ws/1RqHw7T Get your news on the go! Download CBS News mobile apps HERE: http://cbsn.ws/1Xb1WC8 Get new episodes of shows you love across devices the next day, stream local news live, and watch full seasons of CBS fan favorites anytime, anywhere with CBS All Access. Try it free! http://bit.ly/1OQA29B --- "CBS Sunday Morning" features stories on the arts, music, nature, entertainment, sports, history, science, Americana and highlights unique human accomplishments and achievements. Check local listings for CBS Sunday Morning broadcast times.