The Supreme Court will take up a case tomorrow that finds groups often at odds on the same side of this argument.
The case, Shurtleff v. Boston, asks whether a Christian group's flag should be allowed to fly over Boston's city hall.
The city did not approve the Christian group Camp Constitution's flag to fly, after allowing flags honoring everything from gay pride to Argentinian heritage.
The ACLU and the Biden administration have filed briefs supporting Camp Constitution.
The ACLU's brief argues "The city can't designate its flagpole a public forum for private speech, then deny access to an otherwise eligible speaker based on viewpoint."
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