The evangelical pastor and broadcaster D. James Kennedy, whose Coral Ridge Presbyterian Church is a beneficiary of DeVos largess, said in a 1986 sermon that children in public education were being “brainwashed in Godless secularism.” More recently, in 2005, he told followers to “exercise godly dominion” over “every aspect and institution of human society,” including the government.

Jerry Falwell Sr. outlined the goal in his 1979 book “America Can Be Saved!” He said he hoped to see the day when there wouldn’t be “any public schools — the churches will have taken them over and Christians will be running them.”

Vouchers are part of the program. According to an educational scholar, they originally came into fashion among Southern conservatives seeking to support segregation in schools. But activists soon grasped that vouchers could be useful in a general assault on public education. As Joseph Bast, president of the Heartland Institute, which receives support from a DeVos-funded donor group, explained: “Complete privatization of schooling might be desirable, but this objective is politically impossible for the time being. Vouchers are a type of reform that is possible now.”

The DeVoses well understand that, stripped of specious language about reform and choice, such a plan for public education would be deeply unpopular. In 2002, Mr. DeVos Jr. advised a Heritage Foundation audience that “we need to be cautious about talking too much about these activities.”

The public school system faces the most immediate threat, but it is not the only institution at risk. The Christian right has already won a number of key roles in the Trump administration.

The head of the presidential transition, Vice President-elect Mike Pence, is an avid voucher proponent. As governor of Indiana, he expanded a voucher program that now funnels $135 million a year to private schools, almost all of them religious. Mr. Trump’s nominee for attorney general, Jeff Sessions, favors religious tests for new immigrants and objects to chief justices with “secular mind-sets.” The nominee for secretary of health and human services, Tom Price, is a member of a physicians’ organization aligned with conservative Christian positions on abortion and other issues.