Cointelpro

If ever anyone could offer up an actual defense of such activities I'd be happy to listen:

Undercover New York City police officers have conducted covert surveillance in the last 16 months of people protesting the Iraq war, bicycle riders taking part in mass rallies and even mourners at a street vigil for a cyclist killed in an accident, a series of videotapes show.

In glimpses and in glaring detail, the videotape images reveal the robust presence of disguised officers or others working with them at seven public gatherings since August 2004.

The officers hoist protest signs. They hold flowers with mourners. They ride in bicycle events. At the vigil for the cyclist, an officer in biking gear wore a button that said, "I am a shameless agitator." She also carried a camera and videotaped the roughly 15 people present.

Beyond collecting information, some of the undercover officers or their associates are seen on the tape having influence on events. At a demonstration last year during the Republican National Convention, the sham arrest of a man secretly working with the police led to a bruising confrontation between officers in riot gear and bystanders.