Law enforcement agencies across the U.S. are monitoring groups that oppose government policy.

New York – Undercover NYPD officers attended meetings of liberal political organizations and kept intelligence files on activists who planned protests around the country, according to interviews and documents that show how police have used counterterrorism tactics to monitor even lawful activities.

The infiltration echoes the tactics the NYPD used in the run-up to New York's 2004 Republican National Convention, when police monitored church groups, anti-war organizations and environmental advocates nationwide. That effort was revealed by The New York Times in 2007 and in an ongoing federal civil rights lawsuit over how the NYPD treated convention protesters.

 The monitoring was carried out by the Intelligence Division, a squad that operates with nearly no outside oversight and is so secretive that police said even its organizational chart is too sensitive to publish. The division has been the subject of a series of Associated Press articles that illustrated how the NYPD monitored Muslim neighborhoods, catalogued people who prayed at mosques and eavesdropped on sermons.

Investigators with his Cyber Intelligence Unit monitor websites of activist groups, and undercover officers put themselves on email distribution lists for upcoming events. Plainclothes officers collect fliers on public demonstrations. Officers and informants infiltrate the groups and attend rallies, parades and marches.

The document provides the latest example of how, in the name of fighting terrorism, law enforcement agencies around the country have scrutinized groups that legally oppose government policies. The FBI, has collected information on anti-war demonstrators. The Maryland state police infiltrated meetings of anti-death penalty groups. Missouri counterterrorism analysts suggested that support for Rep. Ron Paul, R-Texas, might indicate support for violent militias — an assertion for which state officials later apologized. And Texas officials urged authorities to monitor lobbying efforts by pro Muslim-groups.

The result of those efforts, however, was that people and organizations can be cataloged in police files for discussing political topics or advocating even legal protests, not violence or criminal activity.
http://www.usatoday.com/news/nation/story/2012-03-23/nypd-liberal-groups/53722732/1
http://www.masslive.com/news/index.ssf/2012/03/documents_show_nypd_infiltrate.html

NYPD document: http://hosted.ap.org/specials/interactives/documents/nypd/dci-briefing-04252008.pdf