Katherine Stewart is the author of a new book, The Power Worshippers: Inside the Dangerous Rise of Religious Nationalism. This article, which appeared as an opinion piece in the New York Times, is essential reading to understand the Trump-supported effort to eliminate the separation of church and state, to give religious organizations the right to discriminate against those they do not like, and to open government funding to religious groups. The U.S. Supreme Court will rule in a case called Espinoza v. Montana this spring, a crucial case that gives the conservative Court an opportunity to compel public funding of religious schools. It is a curious fact that libertarians like the DeVos family and the Koch family oppose almost every form of government funding (Social Security, Medicare) except for government money for religious schools.

She writes:

Many Americans know by now that when Christian nationalists talk about “religious freedom” they are really asking for the privilege to impose their religion on other people. What Americans may not yet understand is that they are also demanding money from taxpayers to do so.

Long before Donald Trump hitched his political fortunes to the Christian right, previous Republican administrations had primed the pumps that would send public money flowing toward religious organizations.

In 2002, the George W. Bush administration increased the flow of federal money to faith-based organizations providing services on behalf of the government. Mr. Bush himself insisted that these organizations would not be permitted to discriminate. But in fact the new method of faith-based funding invited the risk of discrimination and the erosion of church-state separation.

The Obama administration, responding to these concerns, put in place provisions to ensure that members of the public were not subject to discrimination on the basis of religious belief or unwanted proselytizing. The provisions also required that users of church-sponsored social programs be made aware of nonsectarian options.

The Trump administration is now proposing to eliminate these Obama-era safeguards. And true to form, they did so earlier this year, on the increasingly Orwellian-sounding annual Religious Freedom Day in January.

One purpose of the new proposed regulations is to make sure that organizations receiving taxpayer money are exempt from the kinds of anti-discrimination law by which nonreligious organizations must abide. If that sounds like a violation of the Establishment Clause of the First Amendment, that’s because it is — or at least it should be.

Under the proposed regulations, faith-based aid organizations that receive public money are free to hire and fire their workers and subcontractors on account of their religion, sexual orientation, or any other behavior or characteristic that the organization finds religiously appealing or objectionable. Aid-providing organizations will no longer have any obligation to let members of the public receiving their services know if there are available nonsectarian options. Organizations that receive their money through vouchers and other forms of indirect aid can now proselytize, require that recipients participate in religious activities or ask that recipients pledge their loyalty to Jesus. And the government itself is no longer required to offer a nonsectarian option for those whose beliefs or conscience make it impossible for them to accept aid on these terms.

“The proposed rules would strip away religious freedom protections from people, often the most vulnerable and marginalized, and even allow faith-based organizations to discriminate in government-funded programs,” Rachel Laser, president and chief executive of Americans United for Separation of Church and State, told me. She added that this puts the interests of these organizations “ahead of the needs of the people seeking critical services.”

Why is the Trump administration so determined to tear down the wall of separation between church and state? The long game is clear: because that’s the way you “take back America” and make it a Christian nation.

But the short game is more relevant now. There is a pile of public money on the other side of the wall that separates church and state, and Christian nationalists are determined to grab it (and to hold on to what they have already grabbed).

These kinds of pro-discrimination rules are bound to cause harm. There may be a woman who loses her job at a faith-based service provider because she is “living in sin” with her partner. There may be people seeking counseling services who will forgo the help they need because it is offered only in conservative Christian health care settings and is staffed with Christian-only providers, all of whom claim to be living in conformity with a “Bible lifestyle.”

There will be some minority-religion providers — a Jewish soup kitchen here, a Muslim job-training initiative there — that will defend the new rules and claim to benefit from them. But they will serve, in effect, as strategic cover, lending the appearance of diversity to a movement that ties the idea of America to specific conservative religious and cultural identities.

Legitimizing these forms of discrimination is itself a grotesque violation of whatever it is that we actually mean by religious freedom. But that’s the point, as far as Mr. Trump and his Christian nationalist allies are concerned. The religious rights of the larger American public are collateral damage in a war of conquest aimed squarely at the public coffers.

To grasp the motivation for the Trump administration in promulgating “religious freedom,” it helps to review a little Supreme Court history. In 2017, the Trinity Lutheran Church of Columbia, Mo., brought a case in which the church claimed that it had an equal claim to government grants for purchasing materials to upgrade its playground.

At the time, many commentators raised a concern that the case was really just a device for eliminating Establishment Clause concerns from decisions affecting the public funding of religious institutions and activities. Lawyers from conservative Christian legal organizations, including the Alliance Defending Freedom, argued that refusing to allocate public money to religious institutions amounted to discrimination against religion. This theory, if it takes hold in law, significantly weakens the Establishment Clause. If withholding taxpayer money from religious institutions amounts to discrimination, then the taxpayer has no choice but to fund religion.

Some important things to know about today’s Christian nationalist movement: It doesn’t believe in the First Amendment as we usually understand it and as our founders intended it. It doesn’t believe that the government should make no law respecting an establishment of religion. It also takes a dim view of government assistance — unless the money passes through churches first. Politically connected religious leaders like Ralph Drollinger of Capitol Ministries, whose White House Bible study has been attended by at least 10 current and former members of Mr. Trump’s cabinet, maintains that social welfare programs have no basis in scripture. “The responsibility to meet the needs of the poor lies first with the husband in a marriage, secondly with the family (if the husband is absent), and thirdly with the church,” Mr. Drollinger has written. “Again, nowhere does God command the institutions of government or commerce to fully support those with genuine needs.”

These ideas are shared by David Barton, a historical revisionist who sits on the boards of an array of Christian nationalist legislative and data initiatives, pastoral networks and other influential groups. Mr. Barton has argued that the Bible and God himself oppose progressive income taxes, capital gains taxes and minimum wage laws. “Since sinful man tends to live in bondage, different forms of slavery have replaced the more obvious system of past centuries,” according to an essay posted to Mr. Barton’s WallBuilders website titled “The Bible, Slavery and America’s Founders.” “The state has assumed the role of master for many, providing aid and assistance, and with it more and more control, to those unable to provide for themselves. The only solution to slavery is the liberty of the Gospel.”

While these activists rail against direct government aid to the poor, they are eager to increase the flow of government handouts to churches and religious groups who may then provide the aid themselves, but without adherence to nondiscrimination law. As a further bonus, when the money gets funneled to religious organizations, some of it then can then be pumped back into the right-wing political machine through religious organizations and the policy groups they support, which act as de facto partisan political cells.

In order to understand the game that Christian nationalists are playing, it’s important to remember that the First Amendment has two clauses concerning religion: one that guarantees the freedom to exercise religion and one that prohibits the government from establishing any religion. What the framers understood is that these two come as a pair; they are necessarily connected. We are free to exercise religion precisely because the government refrains from establishing religion.

At present, the Christian nationalist movement has substantial sources of support in the form of access to wealthy donors and robust donor-advised charities. It also has a large base of supporters who make large numbers of small contributions. But leaders of the movement know that their bread will have a lot more butter if it comes from the government. They already receive significant funding indirectly from taxpayers in the form of deductions and exemptions. They are determined to secure these extra funds, and they are immensely fearful of losing them, especially if a pluralistic society decides to do something about the fact that its tax dollars are being used to fund groups that actively promote discrimination against many citizens and support radical political agendas.

In the future, if the Trump administration has its way, the current flow of taxpayer money to religious organizations may well look like the trickle before the flood. Religious nationalists dream of a time when most or all social welfare services pass through the hands of religious entities. They imagine a future in which a young woman seeking advice on reproductive health care will have nowhere to turn but a state-funded, church-operated network of “counseling” centers that will tell her she will go to hell if she doesn’t have the baby.

The discrimination against individuals and the misuse of public money that the Trump administration’s proposed regulations would allow is bad enough. But these are far from the worst consequences of this kind of assault on the separation of church and state. The most profound danger here is to the deep structure of American society and politics.

In 1786, when Thomas Jefferson and James Madison pushed through the Virginia Statute for Religious Freedom that Religious Freedom Day commemorates, the issue that motivated them and that brought evangelical Christians at the time over to their side was a detested tax imposed on all Virginians to pay for the church services demanded by the established church. “To compel a man to furnish contributions of money for the propagation of opinions which he disbelieves and abhors, is sinful and tyrannical,” Jefferson wrote. “No man shall be compelled to frequent or support any religious worship, place, or ministry whatsoever.”

It is ironic, then, that the Trump administration’s religious freedom initiative seeks to fund religious organizations with taxpayer money. But what makes this particularly dangerous is that the same money in many cases goes to churches and religious organizations that are increasingly and aggressively asserting themselves in partisan politics, and that happen to support Mr. Trump. As Jefferson and Madison understood, the destruction of the wall that separates church and state corrupts politics just as surely as it corrupts religion.