Since the attacks of September 11, 2001, law enforcement agencies have actively sought partnerships with Muslim communities in the UnitedStates. Consistent with community-based policing, these partnerships are designed to persuade members of these communities to share information about possible extremist activity. These cooperative efforts have borne fruit, resulting in important anti-terrorism prosecutions. But during the past several years, law enforcement has begun to use another tactic simultaneously: the FBI and some police departments have placed informants in mosques and other religious institutions to gather intelligence. The government justifies this tactic by asserting that it must take a proactive stance in order to prevent attacks by terrorists from outside the United States, and by so-called homegrown cells from within.The problem is that, when the use of informants in a mosque becomes known in a Muslim community, people within that community -t he same people that law enforcement has so assiduously courted as partners against extremism – feel betrayed. This directly and deeply undermines efforts to build partnerships, and the ability to gather intelligence that might flow from those relationships is compromised or lost entirely.

As it stands, the law-whether in the form of Fourth Amendment doctrine, defenses in substantive criminal law, or cases and statutes supporting lawsuits against government surveillance -offers little help in resolving this dilemma. Further, change in either statutes or SupremeCourt doctrine that might help address the problem seems vanishingly unlikely. Locally-negotiated agreements on the use of informants represent the best alternative route toward both security against terrorists and keeping Muslim communities inclined to assist in anti-terrorism efforts. In these agreements, law enforcement might agree to limit some of its considerable power to use informants in exchange for the continued cooperation of the community. The article discusses how such agreements might be reached, what they might strive to do substantively, and the problems they might encounter.