One of the most important things that separation of religion and government does is ensure that Americans are free to give financial support only to the faiths of their choosing – or support none at all.

That’s the ideal, anyway. Sadly, the Supreme Court has been drifting away from that principle, and during this term, the high court might even rule that under certain circumstances, taxpayers can be compelled to support religious schools.

In a pending case, Espinoza v. Montana Department of Revenue, the justices will consider an appeal of a ruling handed down in December 2018 by the Montana Supreme Court.

The state high court struck down a private school voucher program that used tax credits to divert public funds to private religious schools, finding that it violated the clear language of the Montana Constitution, which protects religious freedom by barring “direct or indirect appropriation or payment from any public fund or monies … for any sectarian purpose or to aid any church, school, academy, seminary, college, university, or other literary or scientific institution, controlled in whole or in part by any church, sect, or denomination.”

Religious freedom protection language like this is found in three-quarters of the state constitutions. It’s designed to ensure that no one is taxed, directly or indirectly, to pay for someone else’s religion.

Opposition to church taxes, no matter what they may be called or what form they may take, has a long history in the United States. As James Madison once argued, if the government can force you to pay even a minuscule amount to support religion, it can compel you to conform in other ways.

“Who does not see that the same authority which can establish Christianity, in exclusion of all other Religions, may establish with the same ease any particular sect of Christians, in exclusion of all other Sects?” Madison wrote in 1785. “That the same authority which can force a citizen to contribute three pence only of his property for the support of any one establishment, may force him to conform to any other establishment in all cases whatsoever?”

In a legal brief filed before the U.S. Supreme Court last week, Americans United joined forces with 17 other civil rights and religious freedom organizations to urge the high court to respect the traditional American principle of private support for religion.

“The founders believed that it was critical to protect individuals’ freedom of conscience against the coercive extraction of tax funds to support religion,” observes the brief. “They also thought it vital to shield religion and religious institutions from the deleterious effects of governmental support and interference: dependency of religious institutions on the state, compromise of religious beliefs, and strife among religious denominations. They therefore exhorted against public subsidies for religious ministries – including religious education, which is not only a vital function of religious ministries but also essential to generating adherents and maintaining those ministries over time and across communities.”

There are many reasons to oppose the diversion of taxpayer money to religious schools. The institutions, for example, are often saturated with a particular form of theology throughout the entire curriculum. They may teach creationism in lieu of modern science or faulty “Christian nation” views of American history.

In addition, many religious schools engage in blatant forms of discrimination. They may refuse to admit students who are LGBTQ, nontheists or religious minorities. Many apply similar religious litmus tests to faculty and staff. Unlike public schools, which are open to all, religious schools serve a private interest.

Finally, any diversion of taxpayer money to religious schools threatens the public education system. Public schools serve 90 percent of America’s children. They ought to be our priority when it comes to allocating taxpayer funding.

All of these reasons are important, but at the end of the day, this is an issue of freedom of conscience. Our founders understood that no one should be forced to support religion against his or her will. It’s one of the primary reasons why they built church-state separation into the First Amendment. The Supreme Court must not abandon this vital principle.

With your help, Americans United will continue to advocate for your right to support religion – or not – as you see fit.