(CNN) -- This summer Cleveland Mayor Frank Jackson has wrestled with one of his biggest challenges since taking office five years ago.
Worried that flash mob violence would overrun city streets as it had elsewhere, the Cleveland City Council unanimously passed legislation that would criminalize the use of Facebook, Twitter and other social media for assembling unruly crowds or encouraging people to commit a crime.
But Jackson, after consulting with advisers, defied the council and vetoed the ordinance -- his first use of that power as mayor.
"It's very difficult to enforce something that's unconstitutional," Jackson said in an interview with CNN. "To make a criminal activity of just having a conversation, whether some acts of criminal activity are associated with it or not, it goes beyond reason."
Jackson suggested that the "emergency measure," as it was described in official records, was perhaps fueled more by emotion than by reason. And on Wednesday, the council members reversed course and voted 14-2 to side with the mayor.
The episode illustrates the challenges facing government officials who try to control social media as a means of combating the sort of spontaneous group violence that has marred London, Philadelphia and other cities this summer. For one, free-speech advocates say such efforts are on shaky constitutional ground. Second, the nature of an open, public Internet makes controlling the flow of social-media messages almost impossible.
"The abuse of these networks and their capabilities hardly justifies recent talk of limiting access, shutting them down, or entrusting corporations and central authorities to monitor them at the expense of our privacy," wrote media theorist Douglas Rushkoff in a commentary for CNN.
In addition, investigations into alleged flash-mob incidents in Cleveland and other cities have unearthed little or no evidence that they were coordinated on the Internet.
The 7-Eleven case
The issue got new life last Saturday when more than two dozen teens ransacked a 7-Eleven store in Germantown, Maryland, a heist recorded by surveillance cameras that became a fast-rising star on YouTube. Montgomery County Police Chief J. Thomas Manger told CNN he believed the youths organized their raid on social networks, and the news media quickly embraced the flash mob angle.
Instead, police later discovered through interviews with suspects that the group was on a bus returning from the county fair when its members decided to raid the convenience store.
"It doesn't appear that Facebook or any of those things were used," said county police Capt. Paul Starks in an interview Thursday. Data reviewed by CNN found no evidence of coordination having taken place on Twitter.
The 7-Eleven episode followed a high-profile series of purported flash mob assaults on the opening night of the Wisconsin State Fair this month. Milwaukee Police Chief Edward Flynn said at a press conference last week that the mobs were not planned or organized via social media.
As this particular breed of flash-mob violence -- group thefts, assaults of bystanders and, in London's case, widespread rioting and looting -- seem to increase in frequency, observers are looking for a common theme. Similar incidents have been reported in recent months in Chicago, Las Vegas, Washington, and St. Paul, Minnesota, and in most cases, social media have become a popular scapegoat.
Instead, the criminal activity has typically occurred when large crowds gather for state fairs and local festivals. The incident in Cleveland that sparked concern there involved unruly teens disrupting a street fair in June. Public Twitter messages at the time contained apparent eyewitness reports, not tweets by young thugs organizing their mayhem.
The concept of sudden, coordinated bursts of violence by gangs of people is not new. Race riots have occurred for centuries. In 1989, gangs of teens in New York attacked random bystanders, an activity that was dubbed "wilding."
The phrase flash mob was coined in 2003 by Bill Wasik, then an editor at Harper's magazine. It was later adopted by Web-savvy folks to describe large choreographed dances and songs in public places, usually organized through digital messaging tools.
In recent years, the term has taken on an additional, darker meaning.
"The hijacking happened a long time ago," Wasik, who chronicled the flash-mob phenomenon in the book "And Then There's This," said in an interview. "Now you have these flash-mob robberies where nobody is sure exactly how these kids decide to do it."
First Amendment issues
Attempts by authorities to squelch digital communications as a way of managing unruly gatherings have largely backfired.
British Prime Minister David Cameron was widely criticized by tech bloggers and free-speech advocates after he proposed imposing limits on the use of social media by rioters in the United Kingdom. As it turns out, many looters there were found to have mobilized not on Twitter or Facebook but through a private messaging system for BlackBerry devices.
"By the time something was on Twitter, it was probably two stages removed from events on the ground," said Mike Butcher, a digital adviser to the London mayor. "You can't predict a riot from social media."
Butcher and other UK authorities initially urged Research in Motion, makers of the BlackBerry, to shut down the BlackBerry Messenger system. But Butcher, not unlike the Cleveland council members, quickly changed his positions.
"There are plenty of innocent people using BlackBerry messaging to warn their loved ones about what's going on," he said.
More recently, Northern California's Bay Area Rapid Transit system tried to stave off a planned protest of BART police shootings in San Francisco by temporarily shutting off cellular service at some stations. Squelch mobile communication, they reasoned, and protesters wouldn't be able to mobilize.
"We stopped service for mobile-phone users," BART spokesman Linton Johnson told CNN, "because they were going to take the very tool that we put in place ... the mobile-phone service safety tool, they were going to turn it around and use it against our customers."
The Electronic Frontier Foundation, a San Francisco-based digital free speech advocacy group, criticized the move as coming from the playbook of Hosni Mubarak, the former Egyptian president who blocked cellular service during citizen protests this year.
"We need to allow speech to occur rather than pre-emptively try to block it," said Jillian York, an Electronic Frontier Foundation director, adding that the BART protest wasn't necessarily organized via digital tools. "I see a lot of stuff happening here that doesn't seem to have a clear origin online."
The U.S. government regularly files requests with Internet and telecom companies to obtain data about their customers. The information aids in tracking criminals, but it doesn't stop them before they get together to commit a crime.
Proposals to do so, as in Cleveland's case, are typically found to be in violation of the U.S. Constitution.
"The Supreme Court has been really strong on First Amendment rights," said Margot Kaminski, executive director of the Information Society Project at Yale Law School. "With the current court that we have and what they've been putting out recently, states are going to have to be really, really careful."
Monitoring social media
If authorities in the United States should learn anything from rulers in the Middle East, said York, it's that the Internet can be a powerful investigative tool. Syria, after banning Facebook for some time, unblocked it once the government was able to monitor activity there, she said.
"There are tools that authorities already have to monitor and pursue criminals," York said. "I'm always kind of surprised when there are calls to block (the Internet). One would think it would be more effective for the police to monitor it."
In Maryland, Milwaukee and elsewhere, police are using the Internet to crack flash-mob cases by posting videos or still images from security tapes and asking citizens to identify people shown in them. And yet many departments complain of being ill-equipped to monitor social-networking chatter.
Authorities in Philadelphia, where flash-mob violence has been among the most severe in the United States over the past few years, have ramped up efforts to monitor social media. Police there issued a news release in February boasting about how detectives were using Facebook to solicit tips and investigate crimes.
The FBI even stepped in to help monitor social-networking sites for mob activity in Philadelphia, The New York Times reported last year. But more recently Philadelphia police have backed off their condemnations of online networks.
"Social networking is not the issue," Police Commissioner Charles Ramsey said last week during a Philly.com online chat. "It's how people are misusing it in order to gather and then commit a crime.
"The media coined the term flash mobs," Ramsey added. "It's not the right term. I prefer the term rampaging thugs."