- Following Super Tuesday, a once-crowded presidential race whittled down to just a handful of Democratic candidates: former Vice President Joe Biden, Vermont Sen. Bernie Sanders, and Hawaii Rep. Tulsi Gabbard.
- All of their major contenders who've ended their campaigns have cast their support behind either Biden or Sanders, endorsing them for president.
- On Sunday, Sen. Kamala Harris became the ninth former candidate to endorse Biden while Sanders has landed just two.
- Warren, who dropped out of the race last week, has yet to endorse one of her former rivals, but all eyes are on her choice.
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Many candidates in the once-crowded primary field have thrown support behind either Sen. Bernie Sanders or former Vice President Joe Biden. Nine former contenders, including former top-tier candidate South Bend, Indiana Mayor Pete Buttigieg, have endorsed Biden. Just two former Democratic candidates - New York City Mayor Bill de Blasio and self-help guru Marianne Williamson - have endorsed Sanders.
Tulsi Gabard, one of the last remaining candidates, has not received any endorsements by candidates who have exited the race.
Warren is the only major candidate who has yet to announce her endorsement.
Endorsements of a candidate by the previous primary rivals are tricky and sometimes contentious. In the 2016 Democratic Primary, Sanders took four weeks to endorse his rival, former Secretary of State Hillary Clinton, after it became clear she would be the party's nominee. The move was unusual, as The Washington Post noted. When Clinton lost the primary race to Obama in 2008, it took her just four days to endorse.
In the 2016 contentious Republican Party primary, then-candidate Trump backtracked on his pledge to support whoever was the party's nominee. Former Ohio Republican Gov. John Kasich, who competed against Trump in 2016, refused to endorse him after Trump won the party's nomination.
Here are the former candidates who have endorsed either Sanders or Biden and the reasons behind their choices.