(Update: Supreme Court on Tuesday sent Colorado case back to the state high court)

The U.S. Supreme Court ruled Monday on a case that public school and First Amendment advocates feared might harm the future of public education in the United States. Will it?

The case is Trinity Lutheran Church v. Comer, in which the Missouri church sued after being denied state funding to refurbish its preschool playground because, it was told, the state Constitution forbids financially supporting a religious institution. Though the policy in the state has since been changed, the case made it to the U.S. Supreme Court, and on Monday, the justices ruled 7 to 2 that the state’s original decision violated the U.S. Constitution’s protection of the free exercise of religion by excluding churches from state programs with a secular intent.

Missouri and several dozen other states have in their constitutions provisions known as Blaine amendments, which forbid the state government from using public funds for “any church, sector or denomination of religion.”

These measures have prevented some legislatures from adopting and implementing school voucher programs — which use public money to pay for private and religious school tuition and other educational expenses — while lower courts have offered different interpretations; for example, the supreme courts in Wisconsin and Arizona upheld voucher programs in their states, while the high court in Colorado declared one unconstitutional.

School-choice supporters argue that the Blaine amendments discriminate against religious institutions while voucher opponents say that they protect the doctrine of “separation of church and state” that has been interpreted as the meaning of the establishment clause and free exercise clause of the First Amendment: “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof.”

First Amendment advocates see the decision as eroding the doctrine of the separation of church and state. For example, Daniel Mach, director of the American Civil Liberties Union’s Program on Freedom of Religion and Belief, said in a statement:

“We’re disappointed in today’s decision. Religious freedom should protect unwilling taxpayers from funding church property, not force them to foot the bill. The court’s ruling, however, focuses specifically on grants for playground resurfacing, and does not give the government unlimited authority to fund religious activity.”

But, in fact, the doctrine has been on a slippery slope when it comes to public funding of tuition at religious schools for some time. There are already 25 voucher programs in 15 states and the District of Columbia, according to EdChoice, a pro-school-choice organization, and one federally funded program in Washington D.C.

President Trump and Education Secretary Betsy DeVos are big supporters of expanding school choice, and DeVos hailed the decision that doesn’t crimp it as favorable. DeVos, who has called traditional public schools a “dead end,” has made clear that expanding school choice is her top priority, and the Trump administration has proposed spending at least $1 billion on a new federally funded voucher program. In a statement, DeVos said:

“This decision marks a great day for the Constitution and sends a clear message that religious discrimination in any form cannot be tolerated in a society that values the First Amendment. We should all celebrate the fact that programs designed to help students will no longer be discriminated against by the government based solely on religious affiliation.”

While the Supreme Court’s ruling is not a broad ruling that strikes down the Blaine amendments, supporters of school voucher programs are already cheering the decision as boding well for the expansion of school choice. On Tuesday, the court sent back to the Colorado Supreme Court a case known as Taxpayers for Public Education v. Douglas County School District. In 2015, the Colorado Supreme Court struck down a school voucher program, saying it violated the Blaine Amendment in the state constitution.

Michael Bindas, a senior attorney with the Institute for Justice, which filed an amicus brief in support of the preschool, said in a statement:

“This decision has implications beyond scrap tires and church playgrounds. The Court’s reasoning sends a strong signal that, just as the Court would not tolerate the use of a Blaine Amendment to exclude a religious preschool from a playground resurfacing program, it will not tolerate the use of Blaine Amendments to exclude religious options from school choice programs.”

It is worth noting again that school choice has spread even with the existence of Blaine amendments in a majority of the states. If the amendments were to be declared unconstitutional, it would obviously be easier for state legislatures to pass state-funded voucher programs — but choice advocates have already found a way to avoid the constitutional issues around voucher programs to succeed in their goal of using public money for private education.

They have done that with several programs, including school tax credit programs, which are voucherlike but set up differently deliberately to get around the issue of state funding going directly to religious schools. These programs offer individuals and corporations tax benefits for donating to organizations that provide “scholarship” money for students to attend private and religious schools. EdChoice says there are now 21 tax-credit scholarship programs in 17 states. In some states, donors can claim state as well as federal tax benefits for the same donation. Opponents say it is akin to legal money laundering.

The bottom line in the Supreme Court’s Trinity decision is that it has shown that it is not against public money being used for secular reasons at a religious institution — and that this could later expand to educational costs. Public education advocates are still hoping the court will set limits on the use of public funds for religious schools, but the tide, at least in the Trump era, is against maintaining church-state protections and protecting the public education system.

While the court did not outright kill the Blaine amendments, it certainly gave heart to school choice advocates who see the court as veering in their direction. That could spell big trouble for those fighting to save what many see as the country’s most important civic institution, the public education system.