Biden: 'I know I'm the front-runner'

Joe Biden laughed off speculation his Democratic rivals were catching up to him in the polls and that his lackluster fundraising efforts posed a problem to his presidential ambitions.

Biden, 76, dominated early polls of the 2020 primary field, buoyed by his name recognition. But the former vice president has slipped in overall support as the race nears the opening Iowa caucuses next February. At the same time, opponent Massachusetts Sen. Elizabeth Warren, 70, has risen in public opinion.