Betsy DeVos. (Andrtew Harrer/Bloomberg)

NO MATTER who won the White House, it was clear that the federal role in education — so muscular during the two previous administrations — would be dialed back. Congress made sure of that when it replaced No Child Left Behind with a law that returns much authority to the states. But the federal government still has a responsibility, especially to students who are most vulnerable and in need. How vigorously President-elect Donald Trump wants to take on that responsibility remains to be seen (his campaign was short on substance), and so his choice of education secretary becomes all the more critical.

After publicly toying with the possible appointment of former D.C. Schools c hancellor Michelle Rhee or charter-school leader Eva Moskowitz for head of the Education Department , Mr. Trump tapped Betsy DeVos, a Michigan philanthropist and school choice activist. Adversaries in the debate over education reform quickly weighed in with praise (a savior and visionary) and condemnation (the end of public education). In fact, Ms. DeVos cannot be easily categorized, which makes her an intriguing choice.

She is not a Trump loyalist, having supported Florida Sen. Marco Rubio and cast her vote as party delegate for Ohio Gov. John Kasich even after Mr. Trump became the presumptive Republican nominee. She traces her 30-year involvement in school reform to wanting other children to have access to the advantages and opportunities her children enjoyed. Hence her support for choice and competition, including by means of charter schools and private-school vouchers. Her commitment to empowering parents, thinking innovatively and taking on entrenched interests is admirable.

But as education secretary, Ms. DeVos will have an obligation to ensure accountability in education — that schools are doing their job, children are learning and resources are fairly distributed and wisely used. There needs to be rigorous questioning by the Senate education committee of her views and her track record. It is concerning, for example, that Michigan has one of the worst systems of oversight over charter schools; that lack of regulation, which Ms. DeVos helped to create, has resulted in some of the worst-performing schools in the nation. Would her support of private-school vouchers result in an expansion to include well-to-do families that do not need the help? What would she do to ensure the protection of gay and transgender students? Would she oppose the deportation of the “dreamers”? And where would she draw the line on local control?

We look forward to hearing answers and hope that in the meantime senators and others will keep an open mind on Ms. DeVos’s nomination.