President Trump’s nomination of Betsy DeVos for education secretary cleared a procedural hurdle in the Senate on Friday, setting up what is shaping up to be a nail-biter for the confirmation vote.

At a rare early-morning session, senators voted along party lines, 52 to 48, to end debate on DeVos’s nomination. A final confirmation vote is expected early next week.

All 48 members of the Democratic caucus are expected to vote against DeVos’s confirmation, along with two Republicans who have expressed their opposition, Sens. Lisa Murkowski of Alaska and Susan Collins of Maine.

That would create a 50-50 tie, which would require a rare tiebreaking vote from the vice president.

The nomination of DeVos, a Michigan billionaire who has spent decades advocating for private-school vouchers, has unleashed a wave of opposition that is unprecedented for a prospective education secretary.

Anti-DeVos callers have been targeting Republican senators, overwhelming their phone lines and clogging their email inboxes. Phone lines in the office of Sen. Patrick J. Toomey (R-Pa.) — who has said he intends to support DeVos — were so overwhelmed that frustrated constituents resorted to fax machines, sending more than 8,000 faxes to Toomey within a 24-hour period late this week, according to the online publication Billy Penn.

Sen. Lamar Alexander (R-Tenn.), chairman of the Senate Committee on Health, Education, Labor and Pensions, has been a stalwart defender of DeVos as she has come under attack. On the Senate floor Friday morning, Alexander praised the nominee as an outsider who has worked for transformational change.

“She’ll be an excellent education secretary in my judgment and an important one for this country,” Alexander said.

Sen. Patty Murray (Wash.), the committee’s ranking Democrat, followed Alexander with a long and pointed argument against confirming DeVos.

“The more people learn about Betsy DeVos, the more they realize how wrong she is for our students and schools,” Murray said, referring to what she said was a “disastrous” confirmation hearing performance in which DeVos stumbled over questions about basic education policy.

“She has no experience with public schools — except through her work trying to tear them down,” Murray said.

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