The senator from California ended her once-promising campaign, saying she lacked the funds to go forward.

Kamala Harris, a US senator from California once considered a promising contender for the Democratic nomination in the 2020 presidential election, ended her campaign on Tuesday.

Harris, in an email to supporters, cited a lack of funding as the main reason for ending her bid to take on US President Donald Trump in a general election.

“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. “My campaign for president simply doesn’t have the financial resources we need to continue.”

Harris held a conference call with staff on Tuesday afternoon to inform them of her decision, sources, speaking on the condition of anonymity, told Reuters News Agency.

The 55-year-old first-term senator, the former attorney general in her home state, had positioned herself as a unifying candidate who could energise the party’s base of young, diverse progressives while also appealing to more moderate voters.

Lagging fundraising and polls

Despite entering the race as an immediate frontrunner, Harris, who was also the only African American woman running, struggled to maintain support, which critics said was fuelled by her inability to articulate policy positions and the backlash of an attempt to attack rival former Vice President Joe Biden’s record on race.

After climbing into double digits in opinion polls following a strong debate performance in June, Harris slid out of the top tier in recent months.

Having raised an impressive $12m in the first three months of her campaign, Harris’s fundraising also fell flat. She was unable to attract the type of attention being showered on Pete Buttigieg by traditional donors or the grassroots firepower that drove tens of millions of dollars to Senators Elizabeth Warren and Bernie Sanders.

Harris had also quickly locked down major endorsements meant to show her dominance in her home state, which offers the biggest delegate haul in the Democratic primary contest.

But allies and critics alike viewed Harris’s message as inconsistent. Her slogan “for the people”, referenced her career as a prosecutor, a record the campaign struggled to pitch to the party’s most progressive voters.

Through the summer, she focused on pocketbook issues and her “3am agenda”, a vow to focus on the issues that wake Americans up in the middle of the night. However, the messages never seemed to resonate with voters.

By the fall, she had returned to her courtroom roots with the refrain that “justice is on the ballot”, both a cry for economic and social justice, as well as her call that she could “prosecute the case” against a “criminal” president

The sagging polls and funds accompanied flagging morale and accusations of listless leadership within the Harris campaign, detailed in an article published by the New York Times newspaper last week.

Her departure from the race is the first of a top-tier candidate from the crowded nominating contest and could now leave a stage of only white contenders in the upcoming December debate in her home state of California. Two minority candidates, Senator Cory Booker and former federal housing chief Julian Castro, remain in the race but neither have yet to qualify for the next debate, which Harris had already qualified for before ending her bid.