US facing a ‘very challenging threat environment’: Lisa Monaco

ABC News’ Pierre Thomas interviews Deputy Attorney General Lisa Monaco on “This Week.” SUBSCRIBE to ABC News: https://bit.ly/2vZb6yP WATCH MORE on http://abcnews.go.com/ THIS WEEK: https://abcnews.go.com/ThisWeek LIKE ABC News on FACEBOOK: https://www.facebook.com/abcnews FOLLOW ABC News on TWITTER: https://twitter.com/abc #ABCNews #ThisWeek #LisaMonaco #PierreThomas #DonaldTrump