Half a century before either Edward Snowden or Chelsea Manning was born, American military codebreakers and U.S. telecommunications companies collaborated on a secret electronic surveillance program that, as newly declassified documents reveal, they knew to be illegal. The program, approved at the highest levels of the U.S. government, targeted messages sent by foreign embassies in Washington, DC, in the years leading up to World War II, and was dramatically expanded after the war.
In a series of oral history interviews recorded in January 1976 by the National Security Agency for internal use, Frank Rowlett, one of the most celebrated American cryptologists, described how the Army Signal Intelligence Service (SIS), which eventually became the NSA, systematically collected copies of cables sent by foreign embassies in Washington during the 1930s. Transcripts of the interviews were classified "Top Secret" until they were declassified this year.
While the SIS's access to diplomatic cables has been known for a long time, the Rowlett interviews reveal something new which is of particular interest today. An NSA historian asked Rowlett if SIS or Army intelligence had given any thought to the legality of using cable traffic after enactment of the Federal Communications Act in 1934, a law that clearly prohibited the interception of any interstate or foreign communication by wire or radio. His answer was unequivocal: "Yes we gave considerable thought to it. We knew it was illegal and therefore we better keep quiet about it."