The constitutionality of St. Louis city's sign ordinance was the topic of debate today in front of a three-judge panel of the Eighth Circuit Court of Appeals.

The case centers around activist Jim Roos, who in 2007 painted a large mural on a South City building he owns protesting the use of eminent domain for private development. The city ordered him to remove the sign, saying it was too big and located in the wrong place. Roos applied for an exemption, calling the mural a work of art. City officials denied the exemption, a decision Roos appealed.

Last March, a federal judge ruled for the city, saying that Roos's mural fell "squarely within the Code’s definition of "sign." The denial of the permit was based solely on the limitations specifically detailed in the Code."

That's the argument city attorney Matt Moak made in a courtroom this morning at the Washington University School of Law

"It could have said I hate the Chicago Cubs or I love the St. Louis Cardinals, it didn’t matter what it said. The fact was it was too big and it was in the wrong location," he said.

Roos's attorney, Michael Bindas with the libertarian Institute for Justice argued that the code on which the city based its decision is, in fact, unconstitutional.

"The same sign, the same size, and the same location would be perfectly permissible if it had certain other content," he said. "For example, if it had a large crest, or a seal of the city of St. Louis."

Those exemptions for things like flags or advertising signs, he says, mean the city's ordinance is based mostly on the content of the sign and is therefore unconstitutional.