SANTA BARBARA, Calif. — When President Trump recently proposed his budget for “school choice,” which would cut more than $9 billion in overall education spending but put more resources into charter schools and voucher programs, he promised to take a sledgehammer to what he has called “failing government schools.” That is harsh language for the places most of us call public schools, and where nearly 90 percent of American children get their education. But in certain conservative circles, the phrase “government schools” has become as ubiquitous as it is contemptuous.

What most people probably hear in this is the unmistakable refrain of American libertarianism, for which all government is big and bad. The point of calling public schools “government schools” is to conjure the specter of pathologically inefficient, power-mad bureaucrats. Accordingly, right-wing think tanks like the Mackinac Center for Public Policy, the Heartland Institute and the Acton Institute have in recent years published screeds denouncing “the command and control mentality” of “government schools” that are “prisons for poor children.” All of these have received major funding from the family of the education secretary, Betsy DeVos, either directly or via a donor group.

The libertarian tradition is indebted, above all, to the Chicago economist Milton Friedman, who published a hugely influential 1955 paper, “The Role of Government in Education.” A true believer in the power of free markets to solve all of humanity’s problems, Friedman argued that “government schools” are intrinsically inefficient and unjustified. He proposed that taxpayers should give money to parents and allow them to choose where to spend education dollars in a marketplace of freely competing private providers. This is the intellectual foundation of Ms. DeVos’s voucher proposals.

But the attacks on “government schools” have a much older, darker heritage. They have their roots in American slavery, Jim Crow-era segregation, anti-Catholic sentiment and a particular form of Christian fundamentalism — and those roots are still visible today.