WASHINGTON (AP) — The future of Sen. Elizabeth Warren's presidential campaign was in serious doubt after she finished a surprisingly weak third in Tuesday's Democratic primary in her home state of Massachusetts.

The disappointing result in the state she represents and a decidedly underwhelming showing in other Super Tuesday contests — she had built an impressive campaign infrastructure stretching across much of the country — marked a striking collapse for the onetime favorite of progressives who was known for having a plan for nearly everything.

On top of mediocre showings in the first four contests — she never finished higher than third place — Warren trailed significantly in the delegate count. Tuesday's results could speed her exit from the race.

Warren finished behind former Vice President Joe Biden, who won the Massachusetts primary, and fellow progressive Vermont Sen. Bernie Sanders, who attracted 10,000-plus people to a rally last weekend on Boston Common — mere miles from Warren's home near Harvard University.

Warren appeared set on remaining in the race, at least for now. Speaking to supporters in Detroit ahead of next week's Michigan primary, she introduced herself as "the woman who's going to beat Donald Trump." The senator encouraged supporters to tune out the results and vote for the person they believed would be the best president, saying: "Prediction has been a terrible business and the pundits have gotten it wrong over and over."

"You don't get what you don't fight for. I am in this fight," she added.

Warren's campaign had all the early markers of success — robust poll numbers, impressive fundraising and a national organization -- but she was squeezed out by Sanders, who had an immovable base of support among progressives she needed to win over. Ahead of Tuesday's vote, Warren's campaign said it was betting on a contested convention — though with a quickly consolidating field that was no sure bet, and she appeared set to enter that convention trailing significantly at least two candidates in the delegate count.

Her lagging performance threatened to force out from the race its last major female contender. Minnesota Sen. Amy Klobuchar dropped out Monday, joining Pete Buttigieg, the former mayor of South Bend, Indiana, to endorse the surging candidacy of Biden. It marked an unexpected twist in a party that had used the votes and energy of women to retake control of the House, primarily with female candidates, just two years ago.

Warren's campaign began with enormous promise that she could carry that momentum into the presidential race. Last summer, she drew tens of thousands of supporters to Manhattan's Washington Square Park, a scene that was repeated in places like Washington state and Minnesota.

Warren, 70, appeared to hit her stride as she hammered the idea that more moderate Democratic candidates, including Biden, weren't ambitious enough to roll back Trump's policies and were too reliant on political consultants and fickle polling.

But Warren was unable to consolidate the support of the Democratic Party's most liberal wing against the race's other top progressive, Sanders. Both support universal, government-sponsored health care, tuition-free public college and aggressive climate change fighting measures while forgoing big fundraisers in favor of small donations fueled by the internet.