BALTIMORE — Education Secretary Betsy DeVos offered an effusive defense of her free-market approach to public education on Monday, saying existing schools have failed too many students and the only answer is to give families an alternative.

Appearing at the national conference of the Education Writers Association, DeVos took a few shots at teachers unions. She said recent teacher strikes have hurt children and disagreements should be handled outside the classroom. And she ramped up her ongoing battle with Randi Weingarten, president of the American Federation of Teachers.

“Great teachers perhaps should be making at least half as much as what Randi Weingarten does at a half-million dollars a year,” she said.

Weingarten replied before the lunchtime event was over. “I’d be delighted if Betsy wants to get all teachers close to $200,000,” she said. “They deserve that — and so much more.”

Last year, Weingarten earned about $406,000 in salary, plus more than $100,000 in expenses and disbursements, according to a government filing.

It was the first time DeVos had appeared before the education writers group. Her willingness to show up was seen as notable, given that she has endured negative coverage since being nominated as education secretary.

“I don’t enjoy the publicity that comes with my position,” she said in an acknowledgment of the tensions. “I don’t love being up onstage nor any kind of platform. I am an introvert.”

DeVos used the appearance to make plain her guiding philosophy that less government is better, as she touted policies that allow children to carry tax dollars with them when they choose private schools.

She recalled putting her children into a private, religious school in Michigan, and her sadness that so many other children in the area couldn’t attend that school. “I realized more and more the unfairness of the situation,” she said.

Her conclusion was that students stuck with what she called traditional, failing public schools lack freedom.

“I entered public life to promote policies that empower all families. Notice that I said families — families, not government,” she said. “I trust the American people to live their own lives and to decide their own destinies. It’s a freedom philosophy.”

DeVos had little to say about improving traditional public schools. Instead, she explained her proposed tax credit is meant to encourage individuals and corporations to donate money to state-run scholarship programs, which would help pay tuition and other expenses for children who want to attend private schools or another alternative. The tax credit would essentially reimburse taxpayers for these donations by offering a dollar-for-dollar reduction in tax liability.

Government accountants refer to such programs as tax expenditures. But DeVos and her aides have vigorously argued that such a program is not government spending because it is allowing taxpayers to keep more of their money.

“In too many stories about this proposal, I see the term ‘public money,’ ” DeVos said. She then quoted former British prime minister Margaret Thatcher as saying that government “has no source of money other than the money people earn themselves.”

“There is no such thing as ‘public money,’ ” DeVos said.