Who’s in the race The other contenders

Susan Rice, 55

Barack Obama’s national security adviser worked closely with Joe Biden when he was vice-president and the two get on well. Has never run for elected office before.

Karen Bass, 66

The California congresswoman leads the Congressional Black Caucus and her star has risen during the vetting process. A force in Washington, she is less well known beyond.

Tammy Duckworth, 52

The Thai-born congresswoman from Illinois was a Black Hawk helicopter pilot and lost both her legs in combat in Iraq. She has been a voice for veterans in the Senate.