The National Security Agency has for the second time in its history been intercepting the international communications of people in the U.S. And James Bamford, author of the groundbreaking books The Puzzle Palace and Body of Secrets, both of which break the NSA wide open and show what’s inside, has written on the topic of the week.

In Operation Shamrock, NSA, with the cooperation of Western Union, was able to copy every telegram entering or exiting the U.S. The company originally provided them on paper tape, then microfilm, and finally on magnetic tape. NSA processed the telegrams using a technique similar to what we now call data mining. Congress got wind of the program, and the Church Committee began investigating it, as part of a wider investigation into intelligence abuses. NSA finally pulled the plug on the program, and Congress passed the Foreign Intelligence Surveillance Act.

Last week, the New York Times revealed that NSA was once again intercepting the international communications of Americans.

According to John E. McLaughlin, who as the deputy director of the Central Intelligence Agency in the fall of 2001 was among the first briefed on the program, this eavesdropping was the most secret operation in the entire intelligence network, complete with its own code word – which itself is secret.

Jokingly referred to as “No Such Agency,” the N.S.A. was created in absolute secrecy in 1952 by President Harry S. Truman. Today, it is the largest intelligence agency. It is also the most important, providing far more insight on foreign countries than the C.I.A. and other spy organizations.

But the agency is still struggling to adjust to the war on terror, in which its job is not to monitor states, but individuals or small cells hidden all over the world. To accomplish this, the N.S.A. has developed ever more sophisticated technology that mines vast amounts of data. But this technology may be of limited use abroad. And at home, it increases pressure on the agency to bypass civil liberties and skirt formal legal channels of criminal investigation. Originally created to spy on foreign adversaries, the N.S.A. was never supposed to be turned inward. Thirty years ago, Senator Frank Church, the Idaho Democrat who was then chairman of the select committee on intelligence, investigated the agency and came away stunned.

“That capability at any time could be turned around on the American people,” he said in 1975, “and no American would have any privacy left, such is the capability to monitor everything: telephone conversations, telegrams, it doesn’t matter. There would be no place to hide.” — New York Times

There’s much more where that came from, and you really should read the entire article. Outside of people with blue badges who actually work in Crypto City, Bamford is easily the expert on NSA, having thoroughly researched the agency for almost 30 years.