WASHINGTON — The Obama administration moved late Friday to prevent a federal judge in California from ruling on the constitutionality of warrantless surveillance programs authorized during the Bush administration, telling a court that recent disclosures about National Security Agency spying were not enough to undermine its claim that litigating the case would jeopardize state secrets.
In a set of filings in the two long-running cases in the Northern District of California, the government acknowledged for the first time that the N.S.A. started systematically collecting data about Americans’ emails and phone calls in 2001, alongside its program of wiretapping certain calls without warrants. The government had long argued that disclosure of these and other secrets would put the country at risk if they came out in court.
But the government said that despite recent leaks by Edward J. Snowden, the former N.S.A. contractor, that made public a fuller scope of the surveillance and data collection programs put in place after the Sept. 11 attacks, sensitive secrets remained at risk in any courtroom discussion of their details — like whether the plaintiffs were targets of intelligence collection or whether particular telecommunications providers like AT&T and Verizon had helped the agency.
“Disclosure of this still-classified information regarding the scope and operational details of N.S.A. intelligence activities implicated by plaintiffs’ allegations could be expected to cause extremely grave damage to the national security of the United States,” wrote the director of national intelligence, James R. Clapper Jr.
So, he said, he was continuing to assert the state secrets privilege, which allows the government to seek to block information from being used in court even if that means the case must be dismissed. The Justice Department wants the judge to dismiss the matter without ruling on whether the programs violated the First or Fourth Amendment.
The filings also included similar declarations from earlier stages of the California litigation, which were classified at the time and shown only to the court but were declassified on Friday. The judge, Jeffrey S. White of the Northern District of California, had ordered the government to evaluate how the disclosures since Mr. Snowden’s leaks had affected its earlier invocations of the state secrets privilege.
The plaintiffs have until late January to file a response. Cindy Cohn, the legal director for the Electronic Frontier Foundation, which is leading one of the cases, called the government’s assertion “very troubling.” She said that despite the Snowden revelations, it was still essentially saying, “We can’t say whether the American people have been spied on by their government.”
Mr. Clapper’s unclassified affidavit to the court — he also filed a classified version, the documents state — contrasts sharply with the findings of President Obama’s advisory committee on signals intelligence, which said in a report made public on Wednesday that the collection of bulk telephone data was of little proven value.
The panel’s experts concluded that “there has been no instance in which N.S.A. could say with confidence that the outcome would have been different” in a terror investigation without the collection of the telephone data. “Moreover, now that the existence of the program has been disclosed publicly, we suspect that it is likely to be less useful still.”
Mr. Clapper, however, suggested that the program was one of many that needed to continue, and he discussed a litany of threats, mostly emanating from Al Qaeda and its affiliates, that he said made the program vital. He argued that revealing additional details, including whom it targets or how companies like AT&T and Verizon have given the N.S.A. access to its equipment and data, would be harmful.
“Disclosing or confirming further details about these activities could seriously undermine an important tool — metadata collection and analysis — for tracking possible terrorist plots,” he wrote, and could reveal methodology, thus “helping foreign adversaries evade detection.”
Still, Mr. Clapper’s description of the program as “an important tool” for tracking possible plots was a downgrade in rhetorical urgency. In earlier, now-declassified court filings, he and other officials had portrayed it as “an essential tool.”
Mr. Obama, in a news conference on Friday, strongly suggested that he was looking for a way to split the difference between these two views. He stopped short of endorsing the advisory group’s recommendation that the data should be held by telecommunications companies or a private consortium that has yet to be created.
“Just because we can do something doesn’t mean we necessarily should,” he said, repeating a line he has used often.
The newly declassified affidavits discuss a now-familiar list of threats to the United States coming from Al Qaeda and groups that share some of its ideology, including a plot in 2006 to blow up airliners over the Atlantic Ocean and the attempted car bombing in Times Square in 2010. But one of the documents makes reference to a renewed effort by Al Qaeda to obtain a nuclear weapon after 2005. It did not cite evidence.
The California litigation over warrantless surveillance represents the remnants of a wave of lawsuits filed in 2006 after The New York Times revealed that the Bush administration had authorized a program of wiretapping without warrants. Most of the initial suits were filed against telecommunications companies and were dismissed after Congress passed a law retroactively immunizing them for participating in the programs.
One of the lawsuits had also named the N.S.A. as a defendant, and in 2008 the Electronic Frontier Foundation refiled a case against the N.S.A. and a series of government officials, challenging the range of domestic surveillance and data collection activities. Several of the claims in those cases have been dismissed, but the First and Fourth Amendment ones remain.
The new filings came five days after another judge, Richard J. Leon of Federal District Court in the District of Columbia, ruled — in a case filed shortly after Mr. Snowden’s first reported disclosures — that the call-logging program in its current form probably violated the Fourth Amendment and called it “almost Orwellian.” The government is expected to appeal that decision.