Today's New York Times reveals the existence of the FBI's domestic intelligence-gathering rules that were revised by the Bush administration in September 2008. The redacted "Domestic Investigations and Operation Guide" was obtained via a FOIA request. According to the Times, "the new rules have given F.B.I. agents the most power in national security matters that they have had since the post-Watergate era."
Here is a snippet that concludes Section 4.2 ("Protection of 1st Amendment Rights"):
In summary, during the course of lawful investigative activities, the FBI may lawfully collect, retain, and consider the content of constitutionally protected speech, so long as: (i) the collectionis logically related to an authorized investigative purpose; (ii) the collection does not actually infringe on the ability of the speaker to deliver his or her message; and (iii) the method of collection is the least intrusive alternative feasible. (p. 27)
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