Ahead of Betsy DeVos’s confirmation hearing Tuesday to be President-elect Donald Trump’s secretary of education, multiple media outlets offered helpful explainers on the “loaded lingo” and specialty terms in debates about America’s schools. The language in these fights is hotly contested, whether it’s private school voucher advocates adopting the term “opportunity scholarships” or charter school critics suggesting charters aren’t really public schools. (They are in fact publicly funded, though they’re run by nonprofits or for-profit companies.)

Perhaps the most nebulous term in these discussions—aside from “school reform” itself—is the simple phrase “school choice.” Sometimes it just means charters, which are strongly supported by the Obama administration and many mainstream Democrats. But it can also mean vouchers, which are generally opposed by the center-left for diverting taxpayer dollars to private schools that may be religious, virtual, or for-profit.

When DeVos appears before the Senate on Tuesday, part of the project for Democrats ought to be drawing distinctions—between charters and vouchers, but also between good charters and bad charters. They may have internal divisions on these issues, but Democrats should recognize that DeVos represents not just an unprecedented threat to public education but the worst of the “school choice” movement.

Republicans will say Democrats are fear-mongering. The Wall Street Journal mocked DeVos’s critics in a weekend editorial, arguing that the nominee “committed the unpardonable sin of devoting much of her fortune to helping poor kids escape failing public schools.” But DeVos, a billionaire Republican donor and former GOP party chair in Michigan, has been a leading financial backer of the worst kind of “school choice” in her state and across America: vouchers, plus charters that are unregulated and unaccountable.

“For choice advocates on the left,” The Washington Post recently reported, “Michigan is a prime example of how not to promote school choice. There is no limit on the number of charter schools; there are dozens of entities with legal power to approve new charters, with varying levels of oversight; and there are too many poor-performing charters, they argue.”

In a devastating analysis last month, Detroit Free Press editorial page editor Stephen Henderson wrote that his newspaper supports successful charter schools, but DeVos’s efforts in Michigan have yielded the opposite. He pointed to his paper’s yearlong investigation, published in 2014, which found that two decades of DeVos-backed charter expansion resulted in “admirable graduation rates, but test scores that look nearly identical to those of public schools.”

“For 20 years, the lobby her family bankrolls has propped up the billion-dollar charter school industry and insulated it from commonsense oversight, even as charter schools repeatedly failed to deliver on their promises to parents and children,” Henderson wrote:

Largely as a result of the DeVos’ lobbying, Michigan tolerates more low-performing charter schools than just about any other state. And it lacks any effective mechanism for shutting down, or even improving, failing charters.

We’re a laughingstock in national education circles, and a pariah among reputable charter school operators, who have not opened schools in Detroit because of the wild West nature of the educational landscape here.

Even if DeVos’s track record with charter schools were sterling, all champions of public education should be disturbed by her support for vouchers. Michigan’s state constitution explicitly prohibits public funding for students to attend private schools, but DeVos and her family poured $5.6 million into a failed effort to change that in 2000. Since then, they’ve spent millions more electing pro-voucher candidates—and defeating anti-voucher candidates—across the country. And as education secretary, DeVos would be poised to implement Trump’s unprecedented $20 billion federal voucher plan, which Vox calledthe biggest change to American public education in half a century.”

Vouchers are a longtime GOP policy priority, but most Democrats have held the line against them, even as President Barack Obama embraced “school choice” through charters. (“The best thing the Obama administration did was what it didn’t do,” education historian Diane Ravitch, a leading left-wing critic of Obama’s education polices, told The New Republic in an interview last month.) Democrats should grill DeVos with the analysis of two political science professors from the University of Richmond—Jennifer Pribble and Jennifer L. Erkulwater—who wrote in The Washington Post Tuesday that vouchers fail even at their own objectives.

“Overall, peer-reviewed research in the United States has found that vouchers have had little, if any, effect on student academic performance or education quality in public schools competing with private voucher schools,” the professors wrote. And in Chile, which already has a nationwide voucher system, the program “has not improved education opportunities for many poor or rural children. Rather, it has increased socioeconomic inequalities and provoked discontent and protest.”

Vouchers also present challenges to the separation of church and state. When public dollars support private religious education, taxpayers may be funding the teaching of creationism and science curriculums that reject the climate change consensus.

In a magazine profile over the weekend, Politico reported that DeVos—a socially conservative Christian who has funded political initiatives against affirmative action and same-sex marriagesees school reform “as the literal battleground for making a more Christian, God-centered society.” (She once talked about achieving “greater Kingdom gain” through school reform than funding traditional Christian organizations.) Stephanie White, the executive director of Equality Michigan, recently told Politico that DeVos may have moderated on LGBT issues over the years, but her personal perspective is irrelevant if federal funding is flowing to anti-gay religious education.

In their testimony on Tuesday, DeVos’s defenders undoubtedly will paint her as qualified and mainstream, even offering some bipartisan cover. Joe Lieberman, Connecticut’s former Democratic senator, is set to introduce DeVos at her hearing. Eva Moskowitz, the Hillary Clinton-supporting Democrat and founder of the Success Academy Charter Schools in New York City, recently praised DeVos as “thoughtful and talented” in The Weekly Standard. But all Democrats—and all defenders of public education—should steadfastly oppose this nomination, even those who believe in “school choice.”