By Aruna Viswanatha
WASHINGTON (Reuters) - A U.S. appeals court on Tuesday grilled opponents of the U.S. government program that collects millions of Americans' phone records, casting doubt on whether it would uphold a lower court ruling that found the program was likely unlawful.
This case is one of a handful brought against the program run by the National Security Agency since its existence was revealed in June 2013 by former NSA contractor Edward Snowden.
U.S. government officials say the program sweeps up numbers dialed and length and time of calls but not the content of communications or the locations of cell phones.
They contend the program, which aims to search for connections to terrorist groups, is legal. Opponents say it violates U.S. citizens' privacy rights.
Experts expect the U.S. Supreme Court to take up the issue once several appeals courts weigh in, if they produce conflicting rulings.
A three-judge appellate panel on Tuesday appeared skeptical of the Washington-based case, brought by conservative lawyer Larry Klayman.
"It seems to be you are telescoping the process in a way that obscures the analysis," Judge Stephen Williams said.
The U.S. Court of Appeals for the District of Columbia Circuit is the second appellate court to hear arguments on whether the NSA program is lawful, after a panel in New York heard arguments in a similar case in September.
Three district courts overall have weighed in. Two courts sided with the government, but Washington federal judge Richard Leon said in December the "Orwellian" program likely violated Americans' 4th Amendment right to be free of unreasonable searches.
The three-judge panel who considered the government's appeal of Leon's ruling on Tuesday, who were all appointed by Republican presidents, pressed both Klayman and a lawyer for advocacy groups that had supported the case about whether the program was substantially different from other methods the government has used to obtain phone data.
Law enforcement officials are able to use other techniques, including trap-and-trace devices, which record outgoing or incoming calls and which require court approval but not the showing of reasonable suspicion that a warrant requires.
"Does one thousand times nothing still equal nothing?" Judge David Sentelle asked, suggesting the NSA program involved collecting more information than other methods, but not qualitatively different information.
(Reporting by Aruna Viswanatha; Editing by Cynthia Osterman)