Elizabeth Warren has ended her once-promising US presidential campaign after failing to finish higher than third place in any of the 18 states that have voted so far.

While the Massachusetts senator said she was proud of her bid, she was also candid in expressing disappointment that a formerly diverse field is essentially now down to two men.

“All those little girls who are going to have to wait four more years,” Warren told reporters outside her home in Cambridge, Massachusetts, as her voice cracked. “That’s going to be hard.”

US presidential election 2020
(PA Graphics)

Known for having “a plan for that,” Warren electrified progressives for much of the past year by releasing reams of policy proposals that addressed such issues as maternal health care, college debt, criminal justice reform and the new coronavirus.

But that energy did not translate into support once voters started making their decisions last month. She failed to capture any of the 14 states that voted on Super Tuesday and finished an embarrassing third in Massachusetts.

The Democratic contest now centres on Bernie Sanders, who is trying to rally progressives, and former vice president Joe Biden, who is appealing to moderates.

They are both white men in their late 70s, a fact that is prompting soul-searching for some Democrats who heralded the historic diversity that characterised the early days of the primary.

While she said she will rally behind whoever emerges as the Democratic nominee, House Speaker Nancy Pelosi also lamented the challenges facing women in politics.

“Every time I get introduced as the most powerful woman, I almost cry because I wish that were not true,” she said. “I so wish that we had a woman president of the United States.”

Elizabeth Warren
Elizabeth Warren has dropped out of the race (Steven Senne/AP)

Tulsi Gabbard is still in the race but faces steep odds and has won just two delegates in her quest for the nomination.

Although she is no longer a presidential contender, Warren is likely to remain a force in Democratic politics and could play a prominent role in a future administration if the party wins the White House.

Clearly aware of her power, Warren did not rush to endorse either Sanders or Biden.

Warren suggested that she would take her time before deciding whom to back. She did not endorse Sanders in 2016, something that infuriated some of his supporters, and only backed Hillary Clinton after she effectively won the nomination.

Sanders wasted little time making an appeal to Warren backers, saying: “I would simply say to her supporters out there, of which there are millions, we are opening the door to you. We’d love you to come on board.”

Bernie Sanders
Bernie Sanders waves to the crowd from the stage at a campaign rally in Arizona (Ross D. Franklin/AP)

But the divisions among Democrats run deep. Toni Van Pelt, the president of the National Organisation for Women, urged Warren against siding with Sanders and noted Biden’s involvement in the passage of the Violence Against Women Act.

“She has a lot of leverage right now. We do trust her to make the right decisions on how to proceed. But we’d like her not to rush into this,” Van Pelt said.

“Sanders doesn’t have a record. He’s really, as far as we know, done next to nothing for women and for our issues and for the things that are our priorities.”

Warren said that “gender in this race, that is a trick question”, since any woman running for office who acknowledges sexism is derided as a “whiner” and those who do not are not accepting reality.

But she nonetheless suggested her road might have been harder than that of the male candidates.

“I was told at the beginning of this whole undertaking that there are two lanes, a progressive lane that Bernie Sanders is the incumbent for, and a moderate lane that Joe Biden is the incumbent for,” she said.

“And there’s no room for anyone else in this. I thought that wasn’t right, but, evidently, I was wrong.”