Already battling controversy over her claimed Native American heritage, Sen. Elizabeth Warren is nearing a decision whether to seek the presidency with a second problem: fissures in the tightknit political operation that has guided her throughout her career.

Mindy Myers, who was one of the primary architects of Warren’s political rise and has remained one of her close advisers, had been expected to play a senior role in the senator’s campaign. But she has been in talks with several rival campaigns and is planning to meet soon with Rep. Beto O’Rourke (D-Tex.), who is considering a presidential run.

Myers ran Warren’s 2012 U.S. Senate campaign and then served as her senate chief of staff, giving her a deep understanding of Warren’s strengths and weaknesses.

Since Hillary Clinton’s defeat in 2016, Warren has been among the top-ranked potential candidates for the 2020 election. She built a massive strategic and get-out-the-vote team to help candidates in the 2018 elections, a move widely seen as a way to both ensure Democratic wins and build alliances in key early presidential states.

But she also stumbled notably in October, when she attempted to put to rest a controversy over her claim to Native American ancestors by releasing DNA results — a move that enraged tribal groups and other minorities concerned about her reliance on a test to measure ethnicity.

That episode injected uncertainty over the decision-making by Warren and her campaign staff and subjected her to both anger and mockery just as she was gearing up for a potential presidential effort.

Those close to Warren have warned recently that while she is still widely expected to enter the race, there remains a chance that she decides against it.

“I don’t have any sense she’s made a final decision that she’s running,” said one Massachusetts Democrat close to her.

Adding to the pressures on her was a cutting editorial Thursday by Warren’s hometown newspaper, the Boston Globe, suggesting she rethink whether to enter the race. The Globe editorial page had called on Warren to run in 2016.

“Warren missed her moment in 2016, and there’s reason to be skeptical of her prospective candidacy in 2020,” the editorial board wrote, pointing out that Republican Gov. Charlie Baker won more votes than she did in their November reelection campaigns.

A recent survey asking Massachusetts voters which candidate they would support in 2020 had Warren in third at just 11 percent even in her home state, which rival campaigns read as a sign of weakness. She trailed former vice president Joe Biden and Sen. Bernie Sanders (I-Vt.). O’Rourke was behind her by only one percentage point.

“Those are warning signs from the voters who know her best,” the Globe wrote in its editorial. “While Warren is an effective and impactful senator with an important voice nationally, she has become a divisive figure. A unifying voice is what the country needs now after the polarizing politics of Donald Trump.”

Myers, as well as other top Warren’s top aides, declined to comment for this article. Some close to the senator said it is possible that she could still have a role in a Warren campaign, but likely not the top job of campaign manager.

That role would likely be filled by another longtime Warren aide, Dan Geldon. Geldon, who was a student in Warren’s class at Harvard Law School, has worked for her in a variety of capacities and has built deep ties among liberal groups that have formed Warren’s base of support. He was director of youth outreach for the Democratic National Committee in 2004, and ran a 2008 House campaign for Rep. John Yarmuth (D-Ky.).

When Warren first ran for Senate and burst onto the national scene by defeating Sen. Scott Brown (R-Mass.), she hired Myers as campaign manager and Geldon as senior adviser.

After she won, Myers became her chief of staff and Geldon was her deputy chief of staff. Myers left in December 2015 to work on electing Senate Democrats, becoming the first woman to lead the Democratic Senatorial Campaign Committee. But she remained in the core nucleus of advisers that Warren relied upon, and was widely expected to return to her operation for the presidential campaign.

“Mindy has been wonderful, and I can’t overstate the positive influence she’s had over the last four years,” Warren said when Myers left her office. “I’m incredibly grateful to Mindy — for helping me win the Senate seat and for working every day to help me use this seat to level the playing field for hard-working families.”

Before working for Warren, Myers ran Sen. Richard Blumenthal’s Connecticut campaign in 2010 and Sheldon Whitehouse’s in Rhode Island in 2006. She has never lost a race.

In a large crop of potential candidates, Warren is one of the few whose presidential decision could significantly affect the rest of the field.

New York magazine in July put her on the cover — jogging to a campaign rally, with the headline “Front Runner?” — and she would enter the race with one of the most daunting fundraising operations. At the end of her Senate reelection, she still had $12.5 million left in her campaign account, giving her an advantage in raising the kind of money needed.

But one of the biggest hurdles she has had to clear is explaining her claim of Native American heritage, which Republican critics, including President Trump, have used to argue she was seeking unfair advantage. A Globe review earlier this year found that ethnicity was not a factor in her career advancements.

In October, she took the extraordinary step of releasing the result of a DNA test that showed that Warren had a Native American ancestor between six and 10 generations ago. She sought to cast it as an ultimate act of transparency, and used it to call on Trump to release his tax returns.

That triggered both blowback from minorities and Native Americans and also criticism that she had submitted to a bully — precisely the opposite of her statements that she would be best positioned to aggressively take Trump on. So far, though, she has not expressed any regrets.

“I put it out there. It’s on the Internet for anybody to see,” she told the New York Times in a recent interview. “People can make of it what they will. I’m going to continue fighting on the issues that brought me to Washington.”

Michael Scherer contributed to this report.