The latest legal victory for civil liberties advocates came at the hands of girls and their parents fighting against a restrictive school dress code.

This week, the U.S. Supreme Court declined to hear a case involving a North Carolina charter school that required female students to wear skirts, which left in place a lower court ruling that struck down the charter school’s dress code as unconstitutional.

“Girls at public charter schools have the same constitutional rights as their peers at other public schools – including the freedom to wear pants,” said Ria Tabacco Mar, director of the Women’s Rights Project at the American Civil Liberties Union, which represented the students and parents in the lawsuit.

SCOTUS’ decision not to hear the case was a blow to conservative religious liberty and school choice groups, which had joined with 10 attorneys general from Republican-led states to ask the Supreme Court to intervene in the case, in hopes it could lead to broader freedoms for charter schools.

The charter school’s founder, Baker Mitchell, issued a statement expressing his disappointment in the court’s decision, saying the court’s opinion “will be applied to charter schools everywhere, threatening their autonomy, subjecting them to the same rules, regulations and political machinations that have crippled government-run school systems.”

While the gendered dress code made the headlines, the case is part of a larger solar system of “school choice” court cases that have the potential to establish how public dollars might be used to fund religious or other private schools.

“This was a case that has enormous stakes for public education, stakes as large as any we’ve seen since the late 1990s,” said Derek Black, professor of law at the University of South Carolina whose research focuses include education law and policy, constitutional law and civil rights.

The crux of the case was about whether charter schools – schools operated by private organizations but funded by taxpayers – are “state actors” and thus legally bound to give their students the same constitutional civil rights as public schools.

“This is a potentially foundational issue,” said Black.

In recent years, school choice and conservative religious groups have pushed harder for more publicly funded educational options. Many argue taxpayer dollars should not only fund traditional public schools but also voucher programs for private schools and public charter schools run by private organizations.

Meanwhile, many proponents of public education contend vouchers and charter schools siphon resources from public schools, risking greater inequality among students. They point out private and charter schools aren’t usually held accountable to the same educational standards and civil rights laws as traditional public schools.

If SCOTUS had taken up the dress code case, it could have upended the nature of public education.

A sex-based dress code

The backstory: Charter Day School, a public charter school in North Carolina, required female students to wear skirts to school based on the view that girls are “a fragile vessel that men are supposed to take care of and honor,” according to the court documents.

A group of female students and parents sued, arguing the sex-based dress code, grounded in gender stereotypes, violated the Equal Protection Clause of the 14th Amendment.

Public institutions, like public schools, can be sued for violation of constitutional rights. But Charter Day School representatives argued that because the charter school is run by a private nonprofit corporation that contracts with the state, it’s not a “state actor.”

Last June, the Fourth Circuit Court of Appeals disagreed, ruling that North Carolina charter schools are a form of public school and are therefore “state actors” subject to the same constitutional requirements as regular public schools.

SCOTUS’ decision not to hear the case upholds that lower court’s ruling.

Why does this matter?

In recent years, conservative school choice advocates have racked up legal wins:

Last summer, SCOTUS struck down Maine’s ban on using public funds at religious schools. The court’s opinion held that if state or local governments subsidize private schools, such as through voucher programs like the one in Maine, they can’t exclude religious schools.

Earlier this month, Oklahoma approved the nation’s first religious charter school. The state will allow the Roman Catholic Archdiocese of Oklahoma City and the Diocese of Tulsa to operate an online school, funded by taxpayer dollars, that will include religious teachings in its curriculum.

The North Carolina case had the potential to take U.S. education further down that path, opening the door for more private and religious schools to enter the educational system with the help of government funding, said Black.

“If there were a green light to have the state basically pay (a church or organization) to run a school, then there would be an enormous number of new applications for charter schools that would dramatically change the financial situation for traditional public schools,” Black said. “It would cause an already small pie to be cut up into smaller pieces.

“For the public school sector, it would be catastrophic.”

But SCOTUS’ decision not to take up the North Carolina case has public school proponents breathing a sigh of relief, he said. And it “throws cold water” on the idea in some progressive circles that the conservative-majority Supreme Court is on a mission to destroy the public school system.

“The school choice folks have been giddy, thinking the sky’s the limit, while the civil rights folks think there is no bottom,” he said. “But I’m sitting here thinking, you’re both off base.”

While conservative school choice groups have seen legal victories, such as with the Maine voucher program, Black believes the North Carolina case “sets a strong precedent” that a situation like Oklahoma’s funding of a Catholic school could be found unconstitutional.