Andrew Harrer/Bloomberg/Getty Images The FBI sent Credo Mobile two national security letters in 2013, demanding that the telecommunications company turn over information about some of its customers.

WASHINGTON ― A federal court has granted permission to a progressive telecommunications company ― one at the center of a years-long battle over the constitutionality of national security letters ― to talk about the ongoing lawsuit it’s involved in.

In 2013, Credo Mobile, a phone company headquartered in San Francisco that raises money for progressive groups, received two national security letters from an FBI special agent in San Antonio, Texas, demanding the names, addresses and billing records associated with three accounts.

National security letters are a controversial tool the FBI uses to secretly compel companies to turn over information about their customers without a court order. Like most national security letters, the two that Credo received prohibited the company from telling anyone ― including its customers ― what the government was asking it to do.

For the past three years, Credo, represented by the nonprofit Electronic Frontier Foundation, has been fighting in court both the constitutionality of the FBI’s request and the bureau’s demand that Credo stay silent. The fight over the legality of the request is ongoing, but earlier this year, the Federal District Court for Northern California said the FBI failed to show the need for the gag order. The government dropped its appeal of that decision, and Credo subsequently published redacted versions of the two national security letters.

Being asked to turn over information about its customers to the FBI put Credo in an awkward situation. Headed by a group of progressive activists, the company prides itself on transparency and has fought against the laws that authorize the government’s use of national security letters. Credo was determined to fight the request, but being forced to stay quiet had a “chilling effect” on its advocacy work, said Becky Bond, who was Credo’s political director when the company received the letter.

Last year, Congress passed the USA Freedom Act, a modified version of the expired Patriot Act, a bill that dramatically expanded government surveillance capabilities. Some civil liberties groups, including the EFF, said the bill was a step in the right direction. But Credo said the changes were superficial and that the new bill essentially reauthorized the most problematic provisions in the Patriot Act.

After the bill was passed, Bond offered a quote for a press release that said Credo was a telecommunications company that was subject to government surveillance. She meant it in a broad sense, but her lawyers said it could be interpreted as an allusion to the ongoing lawsuit. They cut the quote.

Michael Kieschnick, a co-founder of Credo, is confident that he and his colleagues made the right decision in fighting the FBI in court rather than going rogue and speaking publicly about being on the receiving end of a national security letter back in 2013.

“If we violated the gag order, we really would have forfeited a lot of possible power achieved through the courts,” Kieschnick said. “We really wanted to use the issue to change policy through the courts as opposed to [having] a pleasant but short-term thrill over violating it. We wanted to protect our customers and change the rules.”

Other telecommunications companies, like Yahoo and Google, have recently published some of the national security letters they received ― but their ability to do so stems from a provision of the USA Freedom Act that requires the FBI to periodically review its nondisclosure requirements and drop them when they’re no longer necessary.

“It’s a totally one-off basis ― it’s the government deciding on its own, ‘OK, you can publish these,’” Andrew Crocker, a staff attorney at EFF, said of the Yahoo and Google disclosures.

“The government issues hundreds of thousands of national security letters and no court ever looks at them and decides, ‘This is proper and this is improper,’” Crocker continued. “You need a constitutional challenge making sure someone is watching what the government is doing.”

Read the national security letters here:

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