A federal judge ruled late Tuesday that the government can continue to gag an internet servicer provider who received a National Security Letter from the FBI -- five years ago.

Under the Patriot Act, the FBI can use such letters to demand personal records about customers from internet providers, financial institutions and credit card companies without a warrant, and then keep the companies from disclosing even that they'd received such a letter.

The ruling came in a lawsuit brought by the American Civil Liberties Union and the New York Civil Liberties Union on behalf of the ISP. The government maintains that revealing information about the letter could compromise ongoing investigations, even though the letter itself was sent five years ago and has been the subject of press accounts.

"We're deeply disappointed that the court ruled that the FBI can continue to gag our John Doe client, who has been silenced for more than five years," Melissa Goodman, staff attorney with the ACLU National Security Project, said in a release. "This gag – which we continue to believe is unnecessary and unconstitutional – has prohibited Doe from participating in the public debate about the Patriot Act and has been used to suppress key information about the FBI's misuse of NSLs. The FBI's overuse of the NSL gag power has allowed the FBI to manipulate the surveillance debate and to deprive Congress and the public of crucial information that would inform the ongoing congressional debate about this intrusive surveillance power."

The court also ruled that the FBI can continue to suppress an "attachment" to the NSL Doe received, the ACLU said. The ACLU "argued that the attachment, if disclosed, would show that the FBI tried to obtain records that it was not entitled to obtain under the NSL statute."

The ACLU is prevented under the order from even disclosing their client's identity.

"The FBI continues to maintain the gag order even though the underlying investigation is more than five years old and even though the FBI abandoned its demand for records from the ISP over two years ago," the ACLU said.

"In December 2008, the U.S. Court of Appeals for the Second Circuit ruled that parts of the NSL statute's gag provisions were unconstitutional, specifically the sections that wrongly placed the burden on NSL recipients to challenge gag orders, narrowly limited judicial review of gag orders and required courts to defer entirely to the executive branch," they continued. "The court of appeals sent the case back to the U.S. District Court for the Southern District of New York and ordered the government to justify the constitutionality of the gag on Doe. In June 2009, the government submitted its justification for the gag on Doe entirely in secret, in a classified declaration that even Doe's ACLU attorneys couldn't see. While the district court ordered the government to produce an unclassified summary, most of the evidence used to justify the continued gag on the ISP remains a secret."

"Continuing to impose a blanket gag order on our Doe client places a serious burden on his First Amendment rights. It is important that NSL recipients – those with first-hand knowledge of the FBI's actual use and abuse of its NSL power – be allowed to speak out," Larry Schwartztol, a staff attorney with the ACLU National Security Project, said in a statement.

Wired notes that the ISP's president wrote an anonymous letter to the Washington Post in 2007. In it, he wrote:

“Three years ago, I received a national security letter (NSL) in my capacity as the president of a small Internet access and consulting business. The letter ordered me to provide sensitive information about one of my clients. There was no indication that a judge had reviewed or approved the letter, and it turned out that none had. The letter came with a gag provision that prohibited me from telling anyone, including my client, that the FBI was seeking this information. Based on the context of the demand — a context that the FBI still won’t let me discuss publicly — I suspected that the FBI was abusing its power and that the letter sought information to which the FBI was not entitled.”

The ruling is available online here.