WASHINGTON — Betsy DeVos moved closer toward confirmation as education secretary Friday after clearing a major hurdle in the Senate, even as Democrats and labor unions fervently sought another Republican vote against her.

Tensions flew on the Senate floor during an early-morning session, with a senior Republican saying DeVos will make an “excellent” secretary and a top Democrat calling her “one of the worst nominees.” Republicans overpowered Democrats, voting 52-48 to cut off debate on the nomination, setting the stage for a final vote on Tuesday.

DeVos, a billionaire Republican donor, has faced fierce criticism from labor unions for her promotion of school choice. Democrats and teachers’ organizations have accused her of seeking to dismantle public education and divert taxpayer money to charter schools and private school vouchers.

Two Republican senators, Susan Collins of Maine and Lisa Murkowski of Alaska, have said they would vote against her nomination, and others are being bombarded by phone calls and letters from parents and teachers across the country. If all Democrats vote against her and no other Republicans dissent, Vice President Mike Pence would have to break a 50-50 tie to gain DeVos’ confirmation.

Sen. Lamar Alexander of Tennessee, chairman of the Health, Education, Labor and Pensions Committee, praised DeVos’s work in reforming the school system through charter schools.

“Teachers have more freedom and parents have more choices, they are public schools and Betsy Devos is in the forefront of helping create that opportunity for public education,” Alexander said shortly after Friday’s vote limiting debate. He said DeVos will seek to diminish federal control over education and give more power to states and locales on such issues as academic standards, teacher evaluations and vouchers.

“We will be swapping a national school board for what she believes in, which is a local school board,” said Alexander, who served as education secretary under President George H.W. Bush.

But Sen. Patty Murray of Washington, the senior Democrat on the committee, said she strongly opposes DeVos because of her tangled finances and potential conflicts of interest, her lack of experience in public schools and knowledge of basic education issues. Murray complained that the confirmation hearing was rushed and that DeVos didn’t answer all the questions from Democrats.

Even if she is confirmed in what some experts say is the most divisive nomination battle in the department’s history, DeVos is off to an uneasy start.

“Betsy DeVos is committed to privatizing public schools, and diverting public funds into private taxpayer-funded vouchers that would leave far too many students behind,” Murray said.

In addition to the statements of opposition by the two Republican senators, billionaire philanthropist and public education backer Eli Broad also has come out against her.

American Federation of Teachers President Randi Weingarten said that Republican senators are under pressure to oppose DeVos.

“This grassroots outcry crosses party and geographic lines,” Weingarten said. “If the DeVos vote was based on the merits, including what constituents are telling their senators, rather than senators being scared of President Trump, DeVos would not be confirmed.”

DeVos, 59, is the wife of Dick DeVos, heir to the Amway marketing fortune. She has spent more than two decades advocating for charter schools in her home state of Michigan and elsewhere around the country. Her support of anti-LGBT organizations and her advocacy for conservative religious values have also caused concerns that she will be a weak advocate for the LGBT community and other minorities.

Even if she is confirmed in what some experts say is the most divisive nomination battle in the department’s history, DeVos is off to an uneasy start.

“It’s definitely been contentious in an unprecedented way,” said Elizabeth Mann, an education policy fellow at Brookings. “Not having a majority vote when her party controls the Senate and when a member of her party is the White House does not send a signal bipartisan support of her agenda.”

Patrick McGuinn, a professor of political science and education at Drew University said that while DeVos will emerge as “somewhat damaged goods” from the nomination process, that is unlikely to derail her work going forward.

“There is not as much need for the Secretary DeVos to seek compromise across the aisle,” McGuinn said. “Where she may be starting under controversial conditions, the fact remains that Democrats will have a very difficult time blocking her agenda and actions as education secretary.”

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