[William] Binney, a 32-year veteran of the National Security Agency turned whistle-blower, ... described details about Stellar Wind, the N.S.A.'s top-secret domestic spying program begun after 9/11, which was so controversial that it nearly caused top Justice Department officials to resign in protest, in 2004. The decision must have been made in September 2001," Mr. Binney told me [and] cinematographer Kirsten Johnson. "That's when the equipment started coming in." He resigned over this in 2001 and began speaking out publicly in the last year. [Binney] is among a group of N.S.A. whistle-blowers, including Thomas A. Drake, who have each risked everything - their freedom, livelihoods and personal relationships - to warn Americans about the dangers of N.S.A. domestic spying. The N.S.A. has technical abilities that are nearly impossible to defend against if you are targeted. The 2008 amendments to the Foreign Intelligence Surveillance Act, which oversees the N.S.A. activities, are up for renewal in December. Two members of the Senate Select Committee on Intelligence, Senators Ron Wyden of Oregon and Mark Udall of Colorado ... have been warning about "secret interpretations" of laws and backdoor "loopholes" that allow the government to collect our private communications. Thirteen senators have signed a letter expressing concern about a "loophole" in the law that permits the collection of United States data. The A.C.L.U. and other groups have also challenged the constitutionality of the law, and the Supreme Court will hear arguments in that case on Oct. 29.