Graffiti art resides at the intersection of art and architecture. On the art side, it can be best classified as an emotive form; the formal qualities of the artwork are less important than the (often illegal) circumstances under which it is created. From the point of view of architecture and urban planning, graffiti is a sign of decay, of a building under duress.
Below is a video on the case of Mike Baca, a graffiti artist working in Brooklyn. He was arrested while shooting a documentary on graffiti. The exact details of his legal case are murky, but he seems to have originally been sentenced to seven years in prison on vandalism and trespassing charges. After a group called the Graffiti Research Lab intervened and arranged for legal support, his sentence was reduced to three months.
Addendum after accidentally posting this entry before I was finished: Can graffiti be art? We no longer have a reliable way to distinguish between art and non-art, but a whole class of art exists to pose exactly this question, and graffiti is certainly part of that class. My only equivocation is that graffiti art, it seems to me, is the only art form that is fully reducible to its act of creation. In this sense graffiti is closer to folk art than "fine" art, or whatever you want to call it.
And regardless of what the Graffiti Research Lab says, there’s compelling evidence to suggest that the serious crime rate falls when minor crimes, like graffiti, are persecuted. Graffiti artists have been consistently vague about the boundaries between street gang tagging and serious graffiti art. Perhaps it’s not in their interests to do so. In any case, Mike Baca seems remarkably amenable to a three month prison sentence, as if it’s all part of a social contract undergoing constant renegotiation.
The video is courtesy of Current Media.