Biden campaign struggling to shake concerns over age, mental acuity

ABC News’ Mary Bruce reports on the latest in President Joe Biden’s reelection campaign 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 #Biden