On August 18, 2001, two days after potential terrorist Zacarias Moussaoui was detained by the FBI in Minnesota, “the [Minneapolis] field office applied, under the Foreign Intelligence Surveillance Act, for a warrant that would have allowed the agents to examine his notebook computer. FBI headquarters, however, blocked the application for the warrant, concluding that there was no evidence that Moussaoui was ‘acting on behalf of a foreign power.’ The Washington supervisors and lawyers considered that a prerequisite for granting the warrant. The field office kept asking for approval, but headquarters repeatedly resisted.”
– Gerald Posner, Why America Slept, Page 193