White House press briefing on Trump retweeting Britain First videos, Sec'y Rex Tillerson, tax reform

White House Press Secretary Sarah Sanders takes questions from the press followed by analysis from ABC News' "The Briefing Room." SUBSCRIBE to ABC NEWS: https://www.youtube.com/ABCNews/ Watch More on http://abcnews.go.com/ LIKE ABC News on FACEBOOK https://www.facebook.com/abcnews FOLLOW ABC News on TWITTER: https://twitter.com/abc GOOD MORNING AMERICA'S HOMEPAGE: https://gma.yahoo.com/