The Summun religious group, founded in Salt Lake City in 1975, sought to erect a monument to the tenets of its faith, called the "Seven Aphorisms," in a park where there are other monuments.
The mostly Mormon city of Pleasant Grove refused, arguing that the park displays must be related to its history or be donated by groups with longtime community ties, like the Fraternal Order of Eagles that gave the Ten Commandments monument in 1971.
The religious group sued, claiming the decision violated the constitutional right to free speech, and a U.S. appeals court agreed.
Writing for the court, Justice Samuel Alito said the Pleasant Grove monument represented "government speech," exempting it from having to give private groups equal access under the Constitution's free-speech clause.
"It is hard to imagine how a public park could be opened up for the installation of permanent monuments by every person or group wishing to engage in that form of expression," he wrote.
Governments can consider form and message when selecting donated monuments, because to force viewpoint-neutrality would cutter parks and create pressure to remove long-standing and cherished monuments, Alito said.
The U.S. Justice Department supported the city, arguing that a ruling for the religious group could force localities to allow private displays at national parks and historic sites.
The last time the Supreme Court addressed the issue of religious displays on public property was in 2005 when a 5-4 decision allowed a Ten Commandments monument on Texas Capitol grounds as part of a broader presentation.
The Summum group believes Moses received two sets of stone tablets on Mount Sinai -- the Seven Aphorisms, which he destroyed in anger, and the Ten Commandments.
One of the Seven Aphorisms states, "Summum is mind, thought; the universe is a mental creation" while another one states, "Nothing rests; everything moves; everything vibrates."