 -- Michigan billionaire education activist Betsy DeVos was confirmed today to serve as the secretary of education in President Trump’s administration, after Vice President Mike Pence cast a tiebreaking vote in the Senate.

The Senate voted on DeVos’ highly contentious nomination this afternoon, and the tally was split evenly, requiring Pence to use his authority as president of the upper chamber of Congress to break the impasse. This was the first time that a vice president has broken a tie to confirm a Cabinet nominee.

Pence read the vote count 50-50 and then voted himself, rendering the tally 51-50.

The day before the vote, Democrats staged a 24-hour marathon of speeches, with more than 30 lawmakers taking to the floor to urge at least one additional Republican to vote against DeVos and block her confirmation.

“It is hard to imagine a worse choice,” Sen. Elizabeth Warren, D-Mass., said before she read letters from constituents urging her to vote no.

DeVos stirred up vehement opposition from teachers’ unions and all 48 Senate Democrats. Many cited concerns about her support of school vouchers, which critics believe will weaken public schools, and her lack of experience, since she never attended or worked in the public education system. Others cited her lack of familiarity with a landmark law protecting the education needs of disabled children.

She was panned for a gaffe during her confirmation hearing, when she hedged on an answer about guns in schools by saying they might be needed in states like Wyoming to defend against “potential grizzlies.”

DeVos' nomination drew above-average negative reactions from the public, with voters flooding Senate phone lines and email accounts in recent weeks. Sen. Chris Van Hollen, D-Md., said his office received 14,000 calls about DeVos.

In addition to the entire Democratic caucus, two moderate Republicans, Sens. Susan Collins of Maine and Lisa Murkowski of Alaska announced they would not support DeVos.

During a speech announcing her opposition, Collins said DeVos’ focus on charters and vouchers “raises the question of whether or not she fully appreciates that the secretary of education’s primary focus must be on helping states and communities, parents, teachers, school board members and administrators strengthen our public schools.”

Before the confirmation vote, the Senate Health, Education, Labor and Pensions Committee voted along party lines, 12-11, to refer DeVos’ nomination to the full Senate.

ABC News’ Morgan Winsor contributed to this report.