Former New York City mayor Michael Bloomberg, who has been a Democrat, a Republican and an independent, officially registers as a Democrat. The move is significant if he decides to challenge President Trump in 2020.

Michael Bloomberg changes his "orientation"... again.

Former New York City mayor Michael Bloomberg, who has been a Democrat, a Republican and an independent, officially registers as a Democrat. The move is significant if he decides to challenge President Trump in 2020. https://t.co/4HHXV75YsS

— The Associated Press (@AP) October 10, 2018