The US Senate has confirmed President Donald Trump's controversial nominee for education secretary, Betsy DeVos, by the smallest possible margin.
US Vice-President Mike Pence cast the tie-breaking vote to secure her cabinet role, splitting the chamber 50-50.
It was the first time ever that a vice-president has interceded in such a way for a cabinet secretary.
Mrs DeVos, a billionaire who has no experience with public schools, faced a rocky confirmation hearing last month.
Moments after voting ended, she tweeted: "I appreciate the Senate's diligence & am honored to serve as @usedgov Secretary. Let's improve options & outcomes for all US students."
Senate Democrats staged a 24-hour debate into Tuesday to hold up her confirmation.
They hoped their all-night speaking marathon would pressure more Republican senators to oppose the nomination, but their efforts were in vain.
Mr Pence was also the first vice-president to cast a deciding vote in the Senate since 2008, when Dick Cheney voted on a tax adjustment plan.
No Democrats voted in favour of Mrs DeVos. Two Republican senators stood by their plan to oppose her confirmation, leaving the Senate in a deadlock.
Critics say Mrs DeVos, who advocates for charter schools, is not qualified to run the Department of Education.
She faced intense scrutiny before a Senate committee in January, when she made headlines for noting that a Wyoming school might need a gun to defend against grizzly bears.
Labour unions, rights groups and teaching organisations have also spoken out against her nomination.
Groups including the American Federation of Teachers and the Leadership Conference on Civil and Human Rights held protests against Mrs DeVos outside of Congress on Monday evening.
The 59-year-old is a wealthy Republican Party donor and a former Michigan Republican Party chairwoman who has long campaigned for education reform in the state.
Her husband Dick DeVos was a chief executive of the beauty and nutrition giant Amway and her brother is Erik Prince, the founder of the controversial private security company Blackwater.
She is among several of Mr Trump's cabinet picks whom Democrats have been trying to block from being approved.
Democrats said in January they would target eight of Mr Trump's nominees based on their lack of qualifications and policy positions.
Before Mrs DeVos' approval, just six of Mr Trump's cabinet picks had been confirmed, compared with former President Barack Obama's 12 cabinet secretaries at this point in 2009 and 16 of George W Bush's in 2001, according to the Washington Post.
The slowed process is also partly due to the fact that some of Mr Trump's picks have not completed a lengthy vetting process typically required of Cabinet candidates, which helps identify potential conflicts of interest.
Hundreds of staff positions also remain vacant as the fate of 15 of Trump administration's nominees hangs in the balance.