The Little Brown Reader

The memorandum, which the bureau sent to local law enforcement agencies last month in advance of antiwar demonstrations in Washington and San Francisco, detailed how protesters have sometimes used "training camps" to rehearse for demonstrations, the Internet to raise money and gas masks to defend against tear gas. The memorandum analyzed lawful activities like recruiting demonstrators, as well as illegal activities like using fake documentation to get into a secured site.

F.B.I. officials said in interviews that the intelligence-gathering effort was aimed at identifying anarchists and "extremist elements" plotting violence, not at monitoring the political speech of law-abiding protesters.

The initiative has won the support of some local police, who view it as a critical way to maintain order at large-scale demonstrations. Indeed, some law enforcement officials said they believed the F.B.I.'s approach had helped to ensure that nationwide antiwar demonstrations in recent months, drawing hundreds of thousands of protesters, remained largely free of violence and disruption.