The questioning suggested that the justices were finding it hard to identify a principle that would compel the city to accept the Summum monument without creating havoc in public parks around the nation.
“You have a Statue of Liberty,” Chief Justice John G. Roberts Jr. said. “Do we have to have a statue of despotism? Or do we have to put any president who wants to be on Mount Rushmore?”
Can the government accept a statement for display in a playground, Justice Stephen G. Breyer asked, that says “don’t throw food at your brother” but not one that says “pull the dog’s tail”?
Does allowing someone to place a John McCain sign on your front lawn, Justice David H. Souter asked, suggest that you support his candidacy?
Would it be all right, Justice John Paul Stevens asked, for the government to exclude the names of gay soldiers from the Vietnam memorial?
And what was the church’s position, Justice Antonin Scalia wanted to know, about “a monument to chocolate chip cookies”?
The case arrived at the court in unusual doctrinal garb, which explains some of the confusion. The justices are used to thinking about cases involving Ten Commandments monuments under the First Amendment’s religion clauses, which prohibit government establishment of religion and protect its free exercise.
But this case, Pleasant Grove City v. Summum, No. 07-665, involves the First Amendment’s free speech clause. The clause generally forbids the government from discriminating among private speakers in public forums on the basis of the content of their speech.
The Summum church contends that the government can no more discriminate among donated private monuments in public parks than it can among speeches and leaflets.
Governments, however, do not need to give equal time to contrary ideas when they are speaking for themselves. Daryl Joseffer, representing the federal government, said that monuments in public parks were just that kind of government speech.
“If we couldn’t formulate and express viewpoints,” Mr. Joseffer said, “I would be here today in support of neither party.”
In fact, the government supported the city.
Lawyers for the church accepted the point about government speech as a general matter, but they said the city must explicitly adopt the message of the Ten Commandments monument for it to count. The city has said only that the monument reflects the area’s pioneer heritage; it has stopped short of endorsing the religious message on the monument.
Mr. Joseffer said the First Amendment imposes no such adoption requirement. Monuments in public parks, he said, need not “have some formal disclaimer on them saying, ‘I am the United States and I approve this message.’ ”
It is enough, he said, for the government to own the given monument and have the right to display it, “drop it to the bottom of the ocean” or “sell it on eBay.”
Chief Justice Roberts said there was a tension in the city’s position.
“You’re really just picking your poison, aren’t you?” he told Jay A. Sekulow, who represented the city. “The more you say that the monument is government speech” to avoid the free speech clause problem, the chief justice said, “the more it seems to me you’re walking into a trap under the establishment clause.”
Pamela Harris, representing the church, said “the city is a bit on the horns of a dilemma” in that regard. But Ms. Harris’s answers to the series of hypothetical questions, and in particular her insistence that the city must formally adopt the message of the Ten Commandments monument, did not seem to satisfy several of the justices.
Mr. Joseffer had to be pressed to answer the question about excluding the names of gay soldiers. In the end, he said the First Amendment’s free speech clause, at least, places no limits on whom the government chooses to honor.
Justice Scalia agreed. “It seems to me the government could disfavor homosexuality,” he said, “just as it could disfavor abortion.”