The Supreme Court ruled unanimously Wednesday that a small religious group cannot force a city in Utah to place a granite marker in a local park that already is home to a Ten Commandments display.

In a case involving the Salt Lake City-based Summum, the court said that governments can decide what to display in a public park without running afoul of the First Amendment.

Pleasant Grove City, Utah, rejected the group's marker, prompting a federal lawsuit that argued that a city can't allow some private donations of displays in its public park and reject others. The federal appeals court in Denver agreed.

In his opinion for the court, Justice Samuel Alito distinguished the Summum's case from efforts to prevent groups from speaking in public parks, which ordinarily would violate the First Amendment's free speech guarantee.

Alito said "the display of a permanent monument in a public park" requires a different analysis.

Because monuments in public parks help define a city's identity, "cities and other jurisdictions take some care in accepting donated monuments," he said.