After riots, there is often an attempt to explain the outburst as the result of large societal forces. The events in the U.K. have been blamed on growing inequality and the current government's austerity program. The disorder in the U.S. in the 1960s was attributed to racism.
But across U.S. cities, there has never been much of a link between unrest and either inequality or poverty. In fact, the riots of the 1960s were actually slightly more common in cities that had more government spending. Riots were significantly less common in the South, where the Jim Crow laws were making their long overdue exit. This isn't to say that many people involved in riots don't have valid grievances, but plenty of people have serious grievances and don't riot.
There's a lot of sensible stuff to agree with there, which is one reason I am linking and excerpting. Where I'd differ slightly is that I think Mr. Glaeser is buying into the typical Northern conception that the North was somehow less racist than the South. Gene Dattel's Cotton and Race in the Making of America is a useful corrective to that. Racism was less likely to be enacted into law in the North, but in some ways the Southern whites were less racist in part because they were more used to interacting regularly with blacks than Northern whites were.
The Glaeser column goes on:
My colleague Christopher Stone has argued that there is another lesson about fighting riots to be learned from the incidents in the Paris suburbs in 2005, and the violence that didn't happen during the Republican National Convention in New York City in 2004. In France, the police initially arrested relatively few people, but sought serious criminal penalties for those they did arrest. The New York Police Department arrested more than 1,000 people and let them go. The New York strategy protected the city; the French strategy wasn't as effective.
The lesson: Light penalties widely applied and serious penalties applied to a few can both deter unlawful behavior. This is a central conclusion of Gary Becker's path-breaking economic analysis of crime and punishment. But in the case of riots, it is awfully hard to actually prove wrongdoing and extremely important to clear the streets. Arresting widely and temporarily can be far more effective.
...We all want the unrest in the U.K. to end with a minimum of bloodshed and brutality. The best way to achieve that end is with sufficient numbers of police on the streets and gentle but restraining incarceration.
Here you can tell Mr. Glaeser is trained as an economist rather than a lawyer. As "effective" as the New York Republican National Convention arrests may have been, they weren't particularly "gentle" for those arrested, who had their liberty infringed during the time they were apprehended. Some of those arrested and then released were entirely innocent, yet they were punished by being detained, without benefit of a trial. This is not a criticism of the New York Police Department, which, like any large bureaucracy, can be imperfect even if well-run and well-intentioned. But to portray this tactic as a model to be emulated strikes me as a stretch.
Also questionable is Professor Glaeser's unstated assumption that without these mass arrests in New York, there would have been more serious rioting or violence. How does he know that for sure?
The Fourth Amendment is pretty clear on this point — a person has a right not to be seized absent probable cause. Mr. Glaeser's complaint that "in the case of riots, it is awfully hard to actually prove wrongdoing" does not apply in New York, because, first of all, there wasn't a riot going on in New York during the 2004 convention, there were just some protests, and, second of all, the Constitution applies even during riots or times at which the authorities fear riots. The amendment doesn't say you have a right not to be seized, but if it's awfully hard to prove you did anything wrong, they can seize you anyway. It says you have a right not to be seized absent probable cause, period. If Professor Glaeser wants to repeal the Fourth Amendment and replace it with a provision allowing police to seize persons without probable cause and detain them during a time of riot or potential riot, my guess is that his argument that is "effective" wouldn't be enough. He'd have to surmount the objections from Americans who'd be naturally and reasonably concerned that this would eviscerate not only their rights under the Fourth Amendment but also the freedom of speech, petition, and assembly rights enshrined in the First Amendment. Not to mention the habeas rights enshrined in Article I, which are subject to suspension by Congress only "when in cases of rebellion or invasion the public safety may require it." Again, we're not talking about mere fear or threat of a riot, but an actual rebellion or invasion, and even then only if the public safety may require it.