Sanders: 'Clinton must become the next president'

Bernie Sanders, in rousing form Monday, doubled down on his endorsement of Hillary Clinton.

Amid upheaval within the Democratic Party, the socialist senator set aside his disappointment and his supporters' rage over leaked emails that exposed the Democratic National Committee's efforts to kill his campaign during the primaries.

Speaking to the convention hall and on TV nationwide, Sanders said: "Any objective observer will conclude that, based on her ideas and her leadership, Hillary Clinton must become the next president of the United States. The choice is not even close."

Sanders was greeted in the convention hall by a standing ovation that lasted about three minutes despite his repeated attempts to quiet the crowd and start talking.

Delegates in the arena waved "Bernie" signs as he took the stage.