Battles over religious liberty sometimes resemble a schoolyard brawl, with adversaries hurling childish taunts at one another and hulking bullies preying on smaller, weaker opponents — think of the Obama administration's vicious and unrelenting attacks on the Little Sisters of the Poor.

It's appropriate, then, that an important religious liberty case now before the U.S. Supreme Court should center arguments over funding for the resurfacing of a schoolyard playground.

The Supreme Court heard oral arguments yesterday in Trinity Lutheran Church of Columbia v. Comer.

This story began in 2012, when the Trinity Lutheran Church of Columbia, Mo, which operates daycare and pre-school facilities, applied to a program that grants money to non-profit organizations to install rubber playground surfaces. The rubber, from recycled tires, is said to be safer for children and the environment.

The school's application had been ranked high enough on its merits by the Missouri Department of Natural Resources to secure a grant. But the state nixed the grant because of the school's religious affiliation. The Missouri state constitution prohibits giving funding to religious entities.

Trinity Lutheran sued, claiming the prohibition violated both the free exercise clause of the First Amendment and the equal protection clause of the Fourteenth Amendment. The case hinges on whether it is constitutional for a state to exclude religious schools from public aid programs.

Missouri is among two-thirds of states that cling to a law called the Blaine Amendment, that prohibits assisting churches with public money.

Born of bigotry, Blaine Amendments were designed to impede the growth of Catholic parochial schools and the threat they supposedly posed to the Protestant education system that prevailed in most public schools at the time.

James Gottry of Alliance Defending Freedom, which is representing Trinity Lutheran, argued recently in a Washington Examiner op-ed that the intent of the playground resurfacing program was to protect children not to proselytize to them.

"The state program offers a reimbursement grant, not a bag of money for the preschool to spend as it wills. Recipient organizations must install the playground surface first, prior to submitting receipts to the state for reimbursement of part of those costs. Trinity would not be receiving money to offer the gospel road to Jesus; it would be receiving money to offer a rubber road to the balance beam."

Precedent suggests the Supreme Court will rule that laws excluding religious options in school choice programs are unconstitutional. The precedent would be a win that reverberated far beyond the playground. It could influence debate over school vouchers, emboldening school choice advocates to experiment more widely with programs such as tax credits and vouchers.

Trinity Lutheran seems to be in a good position to prevail. On Wednesday, Justice Sonia Sotomayor claimed the Blaine Amendments have an "admirable tradition." But the court's four conservative justices have voted against similar provisions in the past. The court's newest justice, Neil Gorsuch, said yesterday that the provision amounted to "discrimination on the basis of religious status." Justice Anthony Kennedy, who will probably cast the deciding vote has said the amendments have a "shameful pedigree."

Liberal secularists laud the amendments for maintaining a big beautiful wall of separation between church and state. But the "wall of separation" is a phrase that appears nowhere in the Constitution and has no place in constitutional jurisprudence.