Internet Archive founder Brewster Kahle has reason to be proud, for he is the third person in United States history to successfully challenge and defeat a National Security Letter (NSL).

FBI Agents served Kahle with an NSL – a form of subpoena used by the FBI to gather data on terror suspects – last November, sealing the entire process with a gag order that forbid him from discussing  it with anybody but his lawyer. Together with his lawyers at the Electronic Frontier Foundation, Kahle pushed back against the NSL on December 14, filing a complaint to a federal court in San Francisco. Late last month, the FBI agreed to drop the request and unseal certain court proceedings.

While Kahle was unable to provide any details on the nature of the FBI’s request, Wired's Threat Level reports that the FBI was interested in the actions of an unknown user on the Internet Archive’s website, at www.archive.org. He said the NSL’s secrecy requirements were “horrendous,” noting that he couldn’t discuss the letter’s details with fellow employees, board members, or even his own wife.

The relative rarity of a successful NSL challenge leaves the ACLU’s Melissa Goodman wondering about what happens with the “hundreds of thousands of NSLs that haven’t gone challenged.”

Kahle called his victory an “unqualified success,” reveling that his case will show others that it is indeed possible to “push back” against an NSL.

Originally conceived in 1986 as part of the Electronic Communications Act, National Security Letters were initially limited only to investigations against individuals suspected of espionage. However, their purpose expanded considerably in 2001 with the passage of the Patriot Act, which removed the “individualized suspicion requirement” and allowed government agents to issue NSLs when considered “relevant” to an “authorized investigation” in protecting the country’s security interests. Since then, the number of NSLs issued spiked dramatically:  a Department of Justice report claims that up to 143,000 NSLs were issued between 2003 and 2005 – with internal audits finding that up to 10 percent of the letters issued between 2002 and 2007 violate agency guidelines or federal law.

While various courts have attacked NSLs constitutionality, the United States government has successfully appealed each ruling, or short of that, revised the law. Writing in a 2007 ruling that found NSLs unconstitutional, Federal District Judge Victor Marrera noted that “courts have a constitutionally mandated role to play when national security policies infringe on First Amendment rights.”

“A statute that allows the FBI to silence people without meaningful judicial oversight is unconstitutional.”