Richard Wolf

USA TODAY

A federal appeals court panel in New York expressed skepticism Tuesday about the government's continued monitoring of Americans' phone records to guard against terrorism.

In a case that could be headed to the Supreme Court, a three-judge panel of the U.S. Court of Appeals for the 2nd Circuit voiced concern about the reach of the National Security Agency's phone surveillance program, which gathers information about phone calls made and received but does not eavesdrop on their content.

At the same time, the judges appeared dubious of their authority to strike down a program authorized by Congress and approved at regular intervals by the Foreign Intelligence Surveillance Court, which operates in secret. They also seemed inclined to stay any verdict against the government to let other courts weigh in.

If appeals courts in New York and the District of Columbia reach opposite conclusions, as district courts have done, "It would have to be the Supreme Court that would deal with it in that case," said Alex Abdo of the American Civil Liberties Union.

The phone surveillance program, which was among those disclosed by former NSA contractor Edward Snowden last year, already is on life support. President Obama has asked Congress for changes that would leave the data in the hands of private phone companies, not the government. But lawmakers are not expected to act this year.

U.S. District Court Judge Richard Leon granted a preliminary injunction against the program in December, ruling that it may be unconstitutional. But less than two weeks later, District Judge William Pauley ruled that the program was legal.

Tuesday's oral argument, televised live on C-SPAN, dealt with the ACLU's appeal of Pauley's ruling. The government's appeal of the earlier ruling has yet to be heard in Washington.

During the nearly two-hour session, the appeals court judges expressed dismay at the extent of the government's surveillance, which they said could be extended to other private data such as bank records.

"You can collect everything there is to know about everybody," Judge Gerard Lynch said, "and have it all in one big government cloud."

But Assistant Attorney General Stuart Delery, representing the government, warned that the call data collected is a useful tool in the fight against terrorism.

"The purpose of this work is to detect and disrupt future plots," Delery said.