“I’ve taken stock and looked at this from every angle, and over the last few days have come to one of the hardest decisions of my life,” Harris wrote in an email to supporters, announcing her decision.
“My campaign for president simply doesn’t have the financial resources we need to continue,” Harris said.
“I don't know anyone who thought Harris would be dropping out & Biden would be at 50% with black voters in December, after that debate moment in late June... but here we are,” tweeted political analyst Harry Enten.
Harris kept up her jabs at Biden in the second debate - and saw her poll numbers bubble up soon after - but that support faded away over the past four months.
Recent national polls had Harris under 5 percent. She had dropped to the same levels in Iowa, and was even lower in New Hampshire.
The poll slide came as fundraising suffered as well.
The decision by Harris comes just over two weeks before the next Democratic debate on December 19 in Los Angeles - which will be in her home state of California.
At this point, these are the Democrats who will be on stage for the December debate: Biden, Buttigieg, Klobuchar, Sanders, Steyer, and Warren.