The U.S. city of Boston violated the free speech rights of a faith-based group when it refused to fly the organization's Christian flag outside the city hall while approving the flags of other groups, the U.S. Supreme Court has ruled unanimously.

One of the three flagpoles in front of the building, which ordinarily flies the flag of Boston, is occasionally made available to groups seeking to celebrate their backgrounds or to promote causes like gay pride.

In a 12-year period, the city approved 284 requests to raise flags on the third flagpole, The New York Times reported on May 2.

The court's 9-0 decision concerns a unique program in Boston that permits private groups to fly flags of their choosing outside Boston City Hall, said Christian Headlines.

The court noted that the city approved "hundreds of requests to raise dozens of different flags" – that is, until the Christian civic organization Camp Constitution requested that the Christian flag, bearing the cross, be flown.

The city of Boston declined the group's request, arguing it would violate the Establishment Clause of the First Amendment.

The city rejected only one, from Camp Constitution, which says it seeks "to enhance understanding of our Judeo-Christian moral heritage."

FLYING FLAG FOR ONE HOUR

The group's application said it sought to raise a "Christian flag" for one hour at an event that would include "short speeches by some local clergy focusing on Boston's history."

Justice Stephen Breyer wrote in the court's opinion. "The city did not deny a single request to raise a flag until" Harold Shurtleff of Camp Constitution made his request.

Breyer noted that the city had allowed flags of other countries, a flag of a bank, and the LGBT Pride flag to be flown.

"When the government encourages diverse expression — say, by creating a forum for debate — the First Amendment prevents it from discriminating against speakers based on their viewpoint," Breyer wrote in the decision.

"The city's lack of meaning­ful involvement in the selection of flags or the crafting of their messages leads us to classify the flag raisings as pri­vate, not government, speech — though nothing prevents Boston from changing its policies going forward," the judge added.

"For the foregoing reasons, we conclude that Boston's flagraising program does not express government speech," Breyer wrote.

"As a result, the city's refusal to let Shurtleff and Camp Constitution fly their flag based on its religious viewpoint violated the Free Speech Clause of the First Amendment."

The judge quoted a 2001 Supreme Court opinion, writing, "When a government does not speak for itself, it may not exclude speech based on 'religious viewpoint'; doing so 'constitutes impermissible viewpoint discrimination.'"

Joining Breyer in the opinion were Chief Justice John Roberts and Justices Elana Kagan, Sonia Sotomayor, Amy Coney Barrett and Brett Kavanaugh. Justices Samuel Alito, Clarence Thomas and Neil Gorsuch concurred in the judgment and signed separate concurring opinions.

"Under the Constitution, a government may not treat reli­gious persons, religious organizations, or religious speech as second-class," Justice Brett Kavanaugh wrote in his concurring opinion.

In a statement, The New York Times quoted a spokesperson for the city saying, it is "carefully reviewing the court's decision and its recognition of city governments' authority to operate similar programs. As we consider next steps, we will ensure that future City of Boston programs are aligned with this decision."