Seven young artists have sued New York City over its strict anti-graffiti law, saying it violated their constitutional right to free speech.
The group, backed by fashion designer Marc Ecko, argued in federal court that the city went too far by banning people under 21 from possessing spray paint or broad-tipped markers.
Gabriel Taussig, a lawyer for New York City, said the law "strikes a proper constitutional balance between the First Amendment rights (to free speech) and the need to control the long-standing plague of graffiti."
The law took effect at the start of the year.
City Councilman Peter Vallone, who sponsored the law and has sparred with Ecko over the issue, accused the designer of hiding behind free speech rights to promote his video game and brand name.
The city says its aggressive police tactics, which combat even minor vandalism to send a message that no law-breaking will be tolerated, have helped dramatically lower crime. Vallone wants to permanently erase the image of New York in the 1970s and 1980s, when graffiti, much of it obscene, covered subway cars and many buildings.
"Graffiti is on the rise. It's becoming glorified again. We don't have the police we used to and those we have are concentrating on terrorism," he said.
Mr Ecko disagreed: "An 18-year-old can buy cigarettes, vote, and go into the army, but he can't buy a can of spray paint in Manhattan. It's silly."
The feud between Mr Ecko and Mr Vallone erupted last year when Ecko launched a video game featuring graffiti art and later got a city permit for a "block party" that included painting graffiti on mock subway cars.
Mr Vallone saw it as a corporate promotion of Mr Ecko's video game. The suit names Vallone and Mayor Michael Bloomberg, saying they have "waged a personal war against graffiti art and graffiti artists, fueled by their personal, subjective distaste for the art form."