An aggressive graffiti cleaning campaign is under way, graffiti artists are the subjects of large-scale police operations, and lengthy jail sentences now handed down.
But while other events that materialized across the country remained mostly peaceful, Oakland's were marred by window-smashing, flag burning and other forms of vandalism, including aggressive graffiti declaring "Kill Zimmerman" and "F*ck the Police".
"Some tourists and ingenuous foreign journalists may imagine that there is a serious separatist movement here," he writes, in reference to some aggressive regionalist graffiti.
The city's aggressive anti-graffiti campaign "changed the dynamic of a lot of writers in Chicago," Mr. Harper said.
Chicago, as Matt Smith, a spokesman for the Streets and Sanitation Department, proudly told me, has one of the world's most aggressive anti-graffiti programs.
These aggressive acts of graffiti serve neither memory nor victim.
"It made Chicago graffiti an aggressive and competitive sport," said Sebastian Napoli, 32, who began writing graffiti around the city in the 1990s when writers called Chicago "the chocolate city" after the brown paint used to cover their work.
In 2003, the company was approached by the Dutch national railroad, which wanted to be able to detect several kinds of sound that might indicate trouble in stations and on trains (glass-breaking, graffiti-spraying, and aggressive voices).
A July poll sponsored by the Citizens Crime Commission, a nonprofit research organization, shows New Yorkers strongly support enforcement of quality-of-life laws, like those against graffiti-writing or aggressive panhandling.
Her 2010 Hero to Zero stencil "burner", or graffiti masterpiece, shows an aggressive-looking man with a dog on a chain and represents an ex-British soldier who has become mentally unstable on return from Afghanistan.
AARON YOUNG This aggressive young artist, who has turned out graffiti-covered boulders and orchestrated motorcycle performances that result in Pollock-like panels, has built a small white room inside the gallery.
