The ACLU demands to know whether the FBI is issuing National Security Letters for the Department of Defense without statutory authority to do so, "enabling the military to access information to which it is not otherwise entitled and to evade the limits on its own authority to issue NSLs," and whether this is being done without probable cause, without judicial approval, and under gag orders to prevent detection.

In its federal FOIA complaint, the ACLU says it learned that "the FBI may be issuing National Security Letters for the military in DoD investigations" when the Pentagon released records to the ACLU in a separate FOIA lawsuit.

This complaint cites the ever-widening disclosures of FBI abuses of national security letters. In March 2007, the Department of Justice's Office of the Inspector General issued its first report about the FBI's use of national security letters from 2003 to 2005. "The OIG found that the FBI had substantially underreported to Congress the number of NSLs it had issued; that in some cases the FBI issued NSLs even where no underlying investigation had been approved; that some NSL recipients had provided the FBI with information to which the agency was not entitled, including voicemails, emails, and images; and that the FBI issued more than 700 so-called 'exigent letters,' which were authorized neither by the NSL statues nor by any other law."

The complaint continues: "In early 2007, the New York Times also reported that the DoD and the Central Intelligence Agency were issuing NSLs to demand sensitive credit and financial records about people in the United States without court approval, and in some instances, without any clear statutory authority to do so. ...
"In October 2007 and March 2008, the DoD released documents to plaintiffs which revealed that the FBI may be issuing NSLs at the behest of the DoD, thereby enabling the military to access information to which it is not otherwise entitled and to evade the limits on its own authority to issue NSLs. ...

"Additionally, in September 2007, a federal district court judge found one of the NSL statute's non-disclosure provisions to be unconstitutional and struck down that entire NSL statute. Doe v. Gonzales, 500F.Supp.2d 379 (S.D.N.Y. 2007). The court stayed its ruling pending the adjudication of the government's appeal. ...

"In March 2008, the OIG issued a second report about FBI NSL use" covering 2006. "The report found, among other things, that the FBI could not locate supporting documentation for 15% of NSLs and could not locate return information for more than 500 NSL requests; that the FBI diminished the seriousness of violations of internal controls and regulations by characterizing them as 'administrative errors'; that even by the FBI's counts there had been more than 600 potential violations that should have been reported to the Intelligence Oversight Board; and that the FBI improperly issued 'blanket NSLs' to 'cover information already acquired through exigent letters and other informal responses.' With respect to the FBI's gag power, the audit revealed that the FBI imposed gag orders on 97% of NSL recipients, that some NSLs that imposed gag orders did not contain sufficient explanation to justify imposition of the gag orders, and that the FBI improperly imposed gag orders in eight of eleven 'blanket' NSLs that senior FBI officials issued to cover illegal requests made through 'exigent' letters.