Washington - The US Senate has confirmed school choice activist Betsy DeVos as education secretary, with Vice President Mike Pence breaking a 50-50 tie.The Senate historian says it was the first time a vice president had to break a tie on a Cabinet nomination.Two Republicans joined Democrats on Tuesday to vote to derail DeVos' nomination. Democrats cited her lack of public school experience and financial interests in organisations pushing charter schools. DeVos has said she would divest herself from those organisations.Republicans Susan Collins of Maine and Lisa Murkowski of Alaska fear that DeVos' focus on charter schools will undermine remote public schools in their states.In an earlier tweet, President Donald Trump wrote "Betsy DeVos is a reformer and she is going to be a great Education Sec. for our kids!"DeVos, a wealthy Republican donor and longtime school choice advocate, has emerged as one of Trump's most controversial Cabinet picks. Labour unions have bitterly contested DeVos' nomination, fearing that she will undermine public education by promoting charter schools and publicly funded voucher programmes for private schools.Trump stood behind his nominee, accusing Democrats of fighting progress and change."Senate Dems protest to keep the failed status quo," Trump tweeted before the vote on Tuesday. "Betsy DeVos is a reformer!"