When Sen. Elizabeth Warren ended her quest for the White House outside her Cambridge home Thursday, it was the culmination of a dramatic reversal of political fortune.

At the beginning of 2019, national polls showed Warren near the back of the pack. But as the year progressed, she rose steadily, then surged. In October, Real Clear Politics showed Warren taking a national lead over former Vice President Joe Biden.

But then Warren plummeted — and her decline continued for months, right up to a disastrous Super Tuesday that saw her finish third in her home state and left her without a single win around the country.

All of which raises an obvious question: What went wrong?

Peter Ubertaccio, a political scientist and dean of the Tom and Donna May School of Arts and Sciences at Stonehill College, said that while the Warren campaign prided itself on a dizzying array of detailed plans, the Democratic base wanted something else.

“I don’t think Democratic voters were looking for a policy wonk on steroids,” Ubertaccio said. “They have been zeroing in on a candidate who could defeat Donald Trump, and many of them simply weren’t sure Elizabeth Warren could be that candidate.”

In addition, Ubertaccio noted, Warren had a significant structural disadvantage: compared to both Biden and Vermont Sen. Bernie Sanders, she was relatively unfamiliar to voters.

“She had to spend a lot of time introducing herself to people,” Ubertaccio said. “For example, most of her supporters before this race wouldn’t have known that she grew up in Oklahoma. ... Because she had to spend a lot of money introducing herself to people, that’s money that she was spending differently than Biden and Sanders, both of whom have been around for a very long time.”

In Cambridge on Thursday, Warren made a similar point.

“I was told at the beginning of this whole undertaking that there were two lanes: a progressive lane that Bernie Sanders is the incumbent for, and a moderate lane that Joe Biden’s the incumbent for, and there’s no room for anyone else in this,” she said. “I thought that wasn’t right, but evidently, I was wrong.”

If wonkiness and newness contributed to Warren’s exit, another factor may also have played a significant role.

“White men without college degrees do not like Elizabeth Warren,” said Wilnelia Rivera, the president of Rivera Consulting. “If you look at that one data point, especially on Super Tuesday, she bombed.

Rivera said she thinks Warren’s struggles with that particular demographic point to a bigger issue: She was a woman, seeking a job that no woman has ever held, and being held to a different standard than her male competitors as she did so.

“She did everything right,” Rivera said. “And it still didn’t matter.”

In that case, though, how did Warren become the front runner last fall, however briefly?

Rivera’s answer: At that point, the question of who voters supported was still theoretical.

“Voters weren’t making a choice yet,” she said.” But as we got closer to the actual primary calendar beginning, the shift started.”

Of course, Warren’s decline also coincided with her struggles on health care. She refused to say if her approach would hike taxes, released a plan that was criticized as unrealistic, and then said she’d take three years to phase it in.

But Erin O’Brien, a political science professor at the University of Massachusetts, Boston, said she believes that on that particular topic, Warren was scrutinized in a way the men she was running against weren’t.

“Bernie Sanders is an obvious example, with ability to pay for Medicare for All,” O’Brien said. “That was truly not in his plan, yet he never paid politically for that lack of specificity. ... Mayor Pete [Buttigieg], same thing. The Republican Senate was never going to pass his plan, and he didn’t pay for that faulty assumption.”

O’Brien said she thinks Warren’s gender had another damaging effect during her campaign’s final days: it convinced women who wanted to vote for her not to.

“Women left Elizabeth Warren because they perceived others as not thinking of her as electable,” O’Brien said. “They were strategic based on an assumption — unstated, and maybe unknown to them — that electability is associated with two 70-plus-year-old white guys who’s been in politics for over 40 years.”

Ubertaccio also said gender contributed to Warren’s demise.

"We can't divorce a lot of this from the [role] that gender plays in political campaigns," he said. "The data tells us that it plays a role, that the bar is higher."

On Thursday, Warren was asked about how gender affected her candidacy.

“That is the trap question for every woman,” Warren replied. “If you say, ‘Yeah, there was sexism in this race,’ everyone says, ‘Whiner.’ And if you say, ‘No, there was no sexism,’ about a bazillion women think, ‘What planet do you live on?’”

“I promise you this,” Warren added. “I will have a lot more to say on that subject later on.”