A unanimous Supreme Court on Monday again made clear that government may not act with hostility against religion.

This bears repeating because so many leftist ideologues and willfully misguided fellow travelers keep insisting that the First Amendment requires government to erect actively a “wall of separation” between itself and faith so high that one can barely acknowledge the other. That wall of separation claim is nonsense that is not only erroneous but acrid as well.

The First Amendment means that government may not establish or favor one religious denomination over another. It does not empower government to keep the free expression of religion completely away from the public square. Indeed, its aim is to encourage all faiths to flourish publicly unhindered, both in the private and public arenas.

The case at hand, Shurtleff v. City of Boston, arose when Boston refused to allow a Christian group to fly a flag at City Hall Plaza despite allowing other groups to do so. The plaza contains three flagpoles. Two of them permanently display the U.S. and state flags. As for the third pole, it usually displays the flag of Boston. However, there is a tradition of letting private groups hold ceremonies on the plaza and fly their own flags from it instead.

This changed when a Christian group duly and properly reserved the plaza for its ceremony, only to have city officials forbid its flag. In response, the Christian group sued. Bizarrely, the 1st U.S. Circuit Court of Appeals ruled against the Christian group. Now, a 9-0 Supreme Court ruling has wisely reversed the decision.

In the use of the third flagpole, it is abundantly clear that the government of Boston is not expressing its own viewpoint or endorsing the content of the flag. The court's syllabus notes that even if the city claimed it was affirming its solidarity with causes such as Pride week or expressions of ethnonational communities by allowing other nations’ flags to be flown there temporarily, “the connection to other flag-raising ceremonies, such as one held by a community bank, is more difficult to discern.”

Meanwhile, Boston’s own public pronouncements about the use of the plaza said it would “accommodate all applicants.” And the court notes, “Indeed, the city’s practice was to approve flag raisings without exception — that is, until [the Christian group’s] request.”

All nine justices therefore agreed that “Boston’s lack of meaningful involvement in the selection of flags or the crafting of their messages leads the court to classify the third-party flag raisings as private, not government, speech.” The First Amendment not only doesn’t require the government to discriminate against religious expression, but it proactively forbids the government from violating the right to free speech.

“When the government does not speak for itself,” wrote the court, “it may not exclude private speech based on ‘religious viewpoint.'" Citing an earlier case, the justices wrote that that would be impermissible viewpoint discrimination.

It was left to Justice Brett Kavanaugh, in a single-paragraph concurring opinion, to cut through the verbiage and summarize the court’s message in one concluding sentence.

“Under the Constitution,” he wrote, “a government may not treat religious persons, religious organizations, or religious speech as second-class.”

Based on a misapplication of a quote from Thomas Jefferson that carries no constitutional weight, those who oppose religion have tried for decades to treat religious interests as second class — or maybe worse. What they have created with their wall of separation lie is a veritable wall of ignorance. All nine justices of the Supreme Court are right to tear down this wall, and the fact that all nine chose to do so is extremely telling about just how well grounded their position was in the first place.