Karen Lewis, the president of the Chicago Teachers Union, is bracing against the proposed new secretary of Education who has thrown her millions behind private school vouchers and charter schools, calling her a “nightmare” for public education.

Betsy DeVos, a Michigan philanthropist whom president-elect Donald Trump has put forth as his choice to head the federal Department of Education, has championed giving more public money to both privately managed kinds of schools “and all the stuff that has been proven not to work,” Lewis said after giving a lecture at the University of Illinois at Chicago on Wednesday afternoon.

“But she’s an entrepreneur. Think about it. Her family’s money comes from a giant Ponzi scheme,” Lewis continued, referring to the fortune DeVos’ husband’s family made after founding Amway.

“So what else would we expect from somebody like that,” Lewis said. “Don’t ask me why he picked her. I don’t know who put her name on the list. But she’s a nightmare. It’s OK. We can occupy the DOE. We’ve done it before. And I believe in direct action and mass movement, so it’ll happen.”

“We won’t be dignifying personal attacks such as this one,” said John Truscott, a spokesman for DeVos’ family foundation.

A Trump campaign spokesman could not immediately be reached. Emails sent through DeVos’ personal website and to her family’s foundation were not immediately answered.

It’s not yet clear what concrete effects the proposed secretary of Education could actually have on Chicago Public Schools, especially with the passage of a new federal law, the Every Student Succeeds Act, which grants a lot more power to states than its predecessor, No Child Left Behind.

However, DeVos spent millions in Michigan to expand charter schools without much regulation.

That led Lewis to say, “I’m concerned she’s going to try to override the part we have in our contract that puts a cap on charters,” a rider in the recently forged deal between CPS and the CTU that halts the number of charter schools the city can open through 2019 unless it closes existing ones. She added, “It’s the voucher piece that worries me because that bleeds money and resources away from district schools. We need a solution that helps everybody.”

During her talk to the students as part of the university’s “Future of Chicago” series, Lewis renewed her calls for an elected school board as well as more state revenue for schools. She said wealthy school donors who’ve contributed enough in Chicago to get their names on charter schools don’t know what’s best for poor kids and give money that isn’t sustainable.

“I am still confused by this notion that the billionaires and the millionaires know what’s best for kids, and it’s not what they send their children to. ‘Cause I don’t see anyone clamoring for charter schools in certain parts of town. I don’t see them clamoring for charter schools in Wilmette or Winnetka,” she said, referring to two wealthy North Shore suburbs.

“I do know we cannot trust public education to philanthropy. That’s why I think we need to have two ways of dealing with this: We need to have revenue and governance,” she said. “I’m concerned that when something else captures the interest of billionaires, they’ll go running off to chase that dream and take their money with them. That’s not sustainable.”

She’s still “hoping” that legislators in Springfield will come up with pension reform by January, a condition of CPS collecting about $215 million toward teacher retirement costs, money that school board President Frank Clark also is optimistic about receiving.

But Lewis said she fears the worst from CPS’ CEO, who imposed midyear cuts last year: “Knowing Forrest [Claypool], he’ll probably just take out a big giant ax. That’s what they do.”

In response, CPS spokeswoman Emily Bittner said no plans were yet forthcoming, adding that “Until we have reason to think that state leaders will fail to live up to their commitment, it is not responsible to scare CPS school communities.”