These are the 2020 Democrats who Trump is worried about

With the field of Democrats running for president growing more crowded each week, the Trump re-election effort has started to zero in on three of them. But Joe Biden -- who's yet to decide whether he'll join the field -- is thought to be the candidate the campaign is most worried about in a general election contest. Plus, the unfolding drama over the budget, the president's plan for a wall on the border with Mexico, and a looming shutdown gives us plenty of clues about what to expect in the era of divided government.