Amy Klobuchar is dropping out of the 2020 presidential race. That narrows the field to four candidates (after Steyer and Buttigieg also dropped out over the weekend). The remaining candidates are Joe Biden, Bernie Sanders, Elizabeth Warren, and Michael Bloomberg. Someone might mention that Tulsi Gabbard is still running, but it's hard to consider her a real candidate since almost no one is voting for her.
I expected Klobuchar to drop out fairly soon, but I was surprised that it came this quickly. I had thought she would stay in through Super Tuesday (when her home state of Minnesota votes). But she has decided to give Joe Biden a better chance on Super Tuesday. She has endorsed him.
I already liked Klobuchar (even though I didn't vote for her), but this further raises my estimation of her. She decided that choosing a candidate that can beat Trump was more important than feeding her own vanity (she would likely have won Minnesota) -- and she doesn't see Sanders as that candidate.