Democratic presidential hopeful Sen. Kamala Harris, who plunged in the polls amid internal strife in her campaign, dropped out of the 2020 presidential election Tuesday after canceling a major New York City fundraiser.

Harris, a California Democrat, informed staffers of her decision in a morning phone call before tweeting out the news.

“To my supporters, it is with deep regret — but also with deep gratitude — that I am suspending my campaign today,” Harris wrote on her Twitter page.

“But I want to be clear with you: I will keep fighting every day for what this campaign has been about. Justice for the People. All the people.”

In an email message to her supporters, Harris said she her campaign lacked the financial wherewithal to continue.

“I’m not a billionaire. I can’t fund my own campaign. And as the campaign has gone on, it’s become harder and harder to raise the money we need to compete,” she wrote. “In good faith, I can’t tell you, my supporters and volunteers, that I have a path forward if I don’t believe I do.”

Her campaign was being dragged down by stagnant fundraising efforts – contribution levels that barely budged over the year – and allegations that her political operation lacked discipline and strategy.

The disarray inside Harris’ campaign was laid excruciatingly bare in a resignation letter from Kelly Mehlenbacher, the outgoing state operations director, who complained that staffers were being treated appallingly and top officials provided little direction on policy and lacked a viable plan to win the election.

“This is my third presidential campaign and I have never seen an organization treat its staff so poorly,” Mehlenbacher wrote in the Nov. 11 letter obtained by the New York Times.

Mehlenbacher, who landed with former Mayor Michael Bloomberg’s 2020 campaign, said the final straw came when dozens of aides at Harris’ Baltimore headquarters were laid off.

“It is unacceptable that we would lay off anyone that we hired only weeks earlier. It is unacceptable that with less than 90 days until Iowa we still do not have a real plan to win,” she wrote.

The 55-year-old Harris, who was recently overtaken in the polls by Bloomberg, also canceled a high-profile fundraiser scheduled for Tuesday at a law firm in New York City, CNBC reported Tuesday.

The event, expected to take place at the Paul Weiss law firm, was dropped from Harris’ schedule because of a “personal matter” and was not rescheduled.

On Monday, her campaign announced that California Gov. Gavin Newsom would spend two days in Iowa to promote her candidacy to help shore up her lagging poll numbers in the early caucus state.

Newsom, who endorsed her candidacy, was expected to attend a number of events Dec. 14 and 15.

The RealClearPolitics average of Iowa polls put her at 3.3 percent, behind South Bend, Ind., Mayor Pete Buttigieg at 24 percent, Sen. Bernie Sanders at 18.3 percent, Sen. Elizabeth Warren at 17.7 percent, Joe Biden at 16.3 percent and Sen. Amy Klobuchar at 5.3 percent.

Sen. Cory Booker, another Democratic presidential hopeful, called Harris a “trailblazer.”

“I’ve loved serving with her in the Senate and every moment we’ve run into one another on the trail. Her campaign broke barriers and did it with joy. Love you, sister,” the New Jersey Democrat wrote on Twitter.

Buttigieg also noted her withdrawal.

Harris “has spent her career advocating for the voiceless and the vulnerable. I am grateful for her leadership and the courage she brings to the Senate and the national debate. I know she will continue to fight fearlessly on behalf of the American people—and our democracy,” he said in a tweet.

Harris started out strong, drawing more than 20,000 people at her campaign’s January kickoff in Oakland.

She gathered more momentum in June’s Democratic debate when she pressed Biden about his stand on busing and how he worked with two segregationist lawmakers as was a young senator from Delaware.

“It is personal and it was hurtful, to hear you talk about the reputations of two United States senators who built their reputations and career on the segregation of race in this country,” Harris told the former vice president.

But Harris, a former San Francisco district attorney, found herself under attack in subsequent debates and struggled to defend herself on capital punishment and other criminal justice issues while serving as a prosecutor.