Fmr. CIA Dir. Brennan: 'Our cybersecurity vigilance shouldn't end with the election'

03:05

John Brennan, former CIA director, joins Andrea Mitchell to discuss the firing of CISA Director Chris Krebs and upcoming troop withdrawals from Afghanistan. Brennan says that Krebs' firing is "very disruptive of the U.S. Government's cybersecurity activities, because our cybersecurity vigilance should not end with the election. There's an ongoing battle that the U.S. government faces in terms of trying to stop and deter and to undermine those attempts to undermine our cybersecurity."