(The Center Square) – The U.S. Supreme Court ruled 9-0 that the city of Boston censoring a private flag in a public forum solely because it was a “Christian flag” was unconstitutional.

Justice Stephen Breyer wrote the opinion for the court, which was released Monday. Joining him were Chief Justice John Roberts and Justices Sonia Sotomayor, Elana Kagan, Brett Kavanaugh, and Amy Coney Barrett. Three concurring opinions were filed by Kavanaugh, Justice Samuel Alito, who was joined by Justices Clarence Thomas and Neil Gorsuch, and by Gorsuch himself, who was joined by Thomas.

The ruling came nearly five months after Liberty Counsel Founder and Chairman Mat Staver presented oral arguments before the court in January on behalf of Boston resident Hal Shurleff and his Christian civic organization, Camp Constitution.

In Shurtleff v. Boston, Staver argued that Boston’s policy violated the First Amendment by censoring a private flag in a public forum open to “all applicants” merely because the application referred to it as a “Christian flag.”

The case affects the free speech of everyone, Liberty Counsel argues. If Boston can open a public forum for all applicants and close it to disfavored viewpoints, then every government could then censor viewpoints it doesn’t like under the guise that every private speaker in the forum was engaging in government speech, the free market legal organization said.

The case dates back to 2017 when Shurtleff and Camp Constitution asked the city for a permit to raise its flag on a Boston City Hall flagpole to commemorate Constitution Day and Citizenship Day on Sept. 17.

Camp Constitution offers classes and workshops on American history and the U.S. Constitution. It was formed “to enhance understanding of the country’s Judeo-Christian heritage, the American heritage of courage and ingenuity, the genius of the United States Constitution, and free enterprise,” according to its petition.

Boston official Gregory Rooney told Shurleff he denied the request because the city “maintains a policy and practice of respectfully refraining from flying non-secular flags.”

The policy was created out of concern for “the so-called separation of church and state or the Constitution’s establishment clause,” he said. Camp Constitution’s flag “was promoting a specific religion,” he reasoned, which wasn’t “in the city’s best interest to necessarily have that flag flying above City Hall.”

All nine justices disagreed.

Justice Breyer wrote, “… Boston’s refusal to let Shurtleff and Camp Constitution raise their flag based on its religious viewpoint ‘abridg[ed]’ their ‘freedom of speech.’ … Boston concedes that it denied Shurtleff ’s request solely because the Christian flag he asked to raise ‘promot[ed] a specific religion.’ … Under our precedents, and in view of our government-speech holding here, that refusal discriminated based on religious viewpoint and violated the Free Speech Clause.”

Gorsuch, with Thomas joining, also argued using the “Lemon Test,” which has been used by courts as a one-size-fits-all approach to resolve Establishment Clause and First Amendment disputes, was a flawed approach. Courts using a test from the 1971 case, Lemon v. Kurtzman, has led to inconsistent and contradictory decisions over the years.

Gorsuch wrote, “It’s time to let Lemon lie in its grave.”

“How did the city get it so wrong?” he asked. In part, due to Lemon, he answered, which he says was “Issued during a ’bygone era’ when this Court took a more freewheeling approach to interpreting legal texts.”

Using Lemon “bypassed any inquiry into the Clause’s original meaning. It ignored longstanding precedents. And instead of bringing clarity to the area, Lemon produced only chaos,” he wrote. “In time, this Court came to recognize these problems, abandoned Lemon, and returned to a more humble jurisprudence centered on the Constitution’s original meaning.”

Boston choosing to follow Lemon “proved a costly decision,” and provides “a cautionary tale for other localities and lower courts,” he added. “The only sure thing Lemon yielded was new business for lawyers and judges.”

Alito warned, “… courts must be very careful when a government claims that speech by one or more private speakers is actually government speech. When that occurs, it can be difficult to tell whether the government is using the doctrine ‘as a subterfuge for favoring certain private speakers over others based on viewpoint,’ … and … becomes ‘susceptible to dangerous misuse…”

“To prevent the government-speech doctrine from being used as a cover for censorship, courts must focus on the identity of the speaker,” Alito argued. “The ultimate question is whether the government is actually expressing its own views or the real speaker is a private party and the government is surreptitiously engaged in the ‘regulation of private speech.’ … speech by a private individual or group cannot constitute government speech if the government does not attempt to control the message. But control is also an essential element of censorship.”

The unanimous ruling, Staver said, “strikes a victory for private speech in a public forum. This case is so much more significant than a flag. … Government cannot censor religious viewpoints under the guise of government speech.”