The field of candidates for the 2020 Democratic presidential nomination is starting to form, with Sen. Elizabeth Warren, D-Mass., announcing Monday that she has launched a campaign "exploratory committee" — the same step that former housing and urban development secretary Julian Castro took earlier in December. Spoiler alert: Exploratory committees always come to the same conclusion. They're both running.
Actually, who isn’t running? At this point, by some counts, as many as 30 potential Democratic candidates either have expressed interest in taking the plunge or have significant constituencies urging them to do so. If you thought the 2016 GOP debates were crowded, just wait.