It's safe to say that, at the moment, there's no clear leader in the Democratic Party. There's been speculation that Biden, who would turn 78 about two weeks after the 2020 election, could challenge President Trump. And the rumors are not unfounded: Back in late March, Biden said he regretted not running for president in the 2016 election and said maybe he could have defeated Trump. (Other names thrown into the mix as possible Democratic contenders include Sen. Bernie Sanders, Sen. Elizabeth Warren, Sen. Corey Booker, Sen. Kirsten Gillibrand, and Sen. Kamala Harris.)