Can a United States city mandate that a sign announcing a religious event must be smaller than a sign promoting a political candidate?

That’s the issue the U.S. Supreme Court will examine in oral argument today in a case addressing content-based speech restrictions of a city ordinance. Critics say the ordinance conflicts with freedom of speech protections offered by the U.S. Constitution.

The Seventh-day Adventist Church in September filed an amicus brief, or “friend of the court” brief, on behalf of the petitioner in the case, “Reed v. Town of Gilbert.” Church legal counselors said local municipalities could unfairly restrict religious speech on signs or in door-to-door book sales if the Supreme Court doesn’t overrule a lower court’s decision on the matter.

The case stems from an incident in which Clyde Reed, pastor of the Good News Community Church in Gilbert, Arizona, placed temporary signs announcing worship services at an elementary school, where the congregation rented space.

Reed received notice from town officials saying his signs violated a local ordinance stating that temporary signs must be no larger than six square feet and stand no longer than 14 hours. Other types of signs, including political and ideological signs, can be up to 32 square feet in size and stand for many months.

In 2007, Reed filed a lawsuit claiming the ordinance was unconstitutional, but the ordinance was upheld by the Ninth Circuit Court of Appeals in San Francisco, California.

Todd McFarland, an associate general counsel for the Adventist Church, said speech on religious matters is entitled to as much constitutional protection as any other kind of speech under the U.S. Constitution.

“If a local government wants to implement speech restrictions on time, place and manner, those can be acceptable, but they need to treat all kinds of speech the same,” he said.

“We were concerned about the Ninth Circuit interpretation about what is and is not a content-based restriction,” McFarland added. “It could limit religious speech in favor of other types of speech, such as political speech and public service announcements.”

Church leaders say the legal precedent, if not challenged, could embolden more cities to limit religious speech. In some cities, religious groups, such as Adventists, are required to obtain a permit to sell religious books door-to-door, while other groups, such as the Boy Scouts of America, are under no such obligation when soliciting donations.

The Adventist Church is one of numerous organizations that filed an amicus brief noting that restricting religious speech is a violation of the U.S. Constitution’s First Amendment and the Equal Protection clause in the 14th Amendment.

A decision on the case is expected by the end of June.