ARTIST Robert Lederman has been arrested so many times he knows the routine better than some of the police. So when eight plainclothes police confiscated a fellow artist's etchings from a sidewalk display here in SoHo recently, Mr. Lederman could tell the police exactly what they were doing wrong.
''They weren't arresting him, they weren't giving him a ticket, they weren't even giving him a voucher for his art,'' Lederman remembers. ''Never mind the First Amendment issues, that's just stealing.''
The First Amendment is at the heart of a dispute between a group of artists who sell their works on the street and New York City, which is trying to control street vending. Under the city's current laws, artists face a Catch-22: They can be arrested for selling without a license, but licenses are virtually impossible to get. That conflict has led to a federal court case focusing on the question of whether the First Amendment protections that cover free speech extend to visual art.
In the first round of the case, which is now under appeal, the answer was no. Judge Miriam Cederbaum, the district court judge who heard Lederman v. City of New York, disagreed with the artists' claim to First Amendment protection.
In her ruling, Judge Cederbaum wrote that ''written matter is the heartland of the First Amendment,'' and that the ''plaintiff's art does not carry either words or the particularized social and political messages upon which the First Amendment places special value.''
The decision has drawn a full palette of criticism. ''It seems absurd that this is even an issue,'' says David A. Ross, director of the Whitney Museum of American Art here. ''We stand firmly behind the idea that art is equal to other forms of expression and is as protected as speech.''
Mr. Ross is one of a list of art-world figures, among them Claes Oldenburg, Chuck Close, Jenny Holzer, and the Museum of Modern Art, who have pledged support for the street artists.
Gloria Phares, a lawyer who worked on the case through the group Volunteer Lawyers for the Arts, says the decision was surprising.
''It seems a little out of step with trends in First Amendment law,'' she says. ''To say you protect writing but not visual expression is like saying you protect writing in English but not in Spanish - conceptually there's no difference, it's simply a matter of vocabulary.''
First Amendment attorney Floyd Abrams says the First Amendment has always protected artistic endeavors as well as political ones. ''Those protections are not limited to written works,'' he says. ''Dance is protected, art; painting itself has been held protected.''
The city's position is that the vending license requirements don't violate First Amendment rights, according to its attorney Robin Binder.
''We're not saying the First Amendment doesn't apply directly to art,'' she says. ''We're saying it doesn't apply to sales of art.''
Randall Fox, one of two attorneys representing the artists pro bono, disagrees. ''There's a long line of Supreme Court cases that indicate the dissemination of protected material is as protected as the actual material itself,'' Mr. Fox says, citing newspaper vending boxes as an example.
''Right now, the end result of the city's licensing policy is an effective ban on the sale of original art works on the public streets of New York City,'' Fox says.
Vendors selling books, magazines, newspapers, or pamphlets can sell without a license anywhere vending is permitted. The city's street artists argue that visual art deserves the same treatment.
The city considers artists general vendors. That means they face the same problem as every other aspiring New York vendor applying for a permit: a waiting list of 1,000 and little chance of success since the 1979 city council froze the number of vending licenses at 853.
Fox says a lot of artists attempting to get licenses have either been told, ''Oh, you're artists, you don't need one, you're covered under the First Amendment, or that the waiting list is too long, they should go away. They go away, try to sell, and get arrested.''
Lederman, whose 11 arrests led him to co-found an artists' advocacy group called Artists' Response to Illegal State Activities, says some 200 artists have been arrested for selling without a license since 1993. That year, police began responding to pressure from business groups demanding ''quality of life'' improvements - including unimpeded sidewalks - in their areas.
For Catherine Ross, a member of a SoHo neighborhood group trying to establish controls on street artists, quality-of-life concerns are very real.
Her cream-colored building is on a SoHo street inundated with traffic on the weekends. ''It's dangerous,'' she says. ''If someone tripped and hurt themselves, would they go after the person who left art on the sidewalk? They'd sue the building.''
Even though her street is a historical landmark area off limits to vending, there are sometimes as many as five vendors in front of her building.
''When they leave, I have to clean up,'' says Ms. Ross, whose husband is an artist. ''Art is important, but it shouldn't be made at the expense of other people's lives.''
The city councilwoman for the area, Kathryn Freed, says the attempt to control vending in SoHo is a matter of safety.
''SoHo has controls on vending because the sidewalks - which are vaulted or hollow - just get too crowded,'' Ms. Freed says. ''First Amendment protections still mean you have to abide by the same laws as everyone else.''
Public safety played a large part in the city's defense. ''The city regulates the streets for the benefit of public safety and welfare,'' says New York City attorney Binder. ''It's entitled to do that.''
Freed has proposed alternative spaces in SoHo, including centrally located lots and co-op galleries, for the artists to exhibit and sell.
''It would be ghettoizing us,'' says Lederman.
The artists' appeal will be heard, at the earliest, in late March. If the decision stands as it reads at the lower court level, attorney Fox says it would leave serious questions about where art fits into the constitutional scheme.
On a political level, Fox says one of the easiest solutions would be to extend to artists the exemption already in effect for written matter.
But councilwoman Freed says this still poses difficulties. ''That's fine when you have 10 or 100 artists, but what if you have a thousand? Where are the limits? How do you decide what constitutes art? And where does schlock start - at Elvis on velvet?''
Ross, of the Whitney Museum, says if the artists pose a problem to the city, it's a ''wonderful problem.''
''Artists bring New York a spirit and energy. It's just a question of how to manage the wealth of artistic talent here and make New York a more interesting place to visit and live.''