The FBI assembled around 300 pages of files on John Lennon in 1971-72, part of President Nixon's effort to deport Lennon to silence him as a critic of the war in Vietnam.
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The files were released to University of California, Irvine, historian Jon Wiener, who wrote about them in his book "Gimme Some Truth: The John Lennon FBI Files." Portions of the files had been withheld under the claim that releasing them would "endanger the national security." With the help of the ACLU of Southern California, Jon Wiener sued the FBI under the Freedom of Information Act, asking the courts to order release of the withheld portions of the Lennon FBI file.
On Dec. 19, 2006, the FBI agreed to release the ten documents that were still being withheld, bringing to an end 23 years of litigation.