Interesting report on how two different riots were handled by the Oakland, California police:

When Oakland police declared an unlawful assembly last year, mayhem ensued uncontrolled. People broke from the crowd into small groups, started fires and smashed dozens of windows near Oakland City Hall.

This time, when the order was given, it was clear the officers had a plan to execute and carried it out swiftly and effectively. The skirmish line pushed the crowd out of downtown and within an hour, it was virtually all over.