A federal judge on Friday questioned the strength of a key lawsuit challenging the constitutionality of the government’s Internet surveillance program known as “upstream” data collection.

Judge Jeffrey White heard oral arguments by attorneys from the Electronic Frontier Foundation, which filed the suit, and the government, during a hearing in a federal district court in Oakland, California. The EFF says its suit is the first challenge in public court to the government’s upstream data program, which copies online data from the main cables connecting Internet networks around the world.

The EFF first filed its suit in 2008 after an AT&T technician provided evidence that the company routed copies of its Internet traffic records to the NSA.

The National Security Agency program is unconstitutional because it collects communications, including content such as email, of people without ties to issues of national security, EFF attorney Richard Wiebe told the judge. That’s an overly broad dragnet that violates the Constitution’s Fourth Amendment protections against unreasonable search and seizure, he said.

U.S. Justice Department attorney James Gilligan did not deny the government taps the Internet’s backbone to gather data. But the government uses filtering mechanisms to automatically destroy certain communications records within milliseconds, he said.

Judge White could declare the upstream collection program unconstitutional, a ruling the government would probably appeal. But on Friday, he questioned whether there was enough evidence on either side to say whether the program is constitutional.

The judge’s ruling might take months, judging from the number and complexity of questions he asked Friday.

“What evidence is there that it’s all international communications [gathered], not just communications with suspected terrorists or hot spots?” he asked EFF attorney Wiebe.

Wiebe cited a top-secret 2009 report by the NSA inspector general detailing the government’s email and Internet data collection, published by The Guardian. Other documents, including AT&T’s first surveillance transparency report, published earlier this year, provide evidence of the program’s reach, he said.

But the government has never confirmed nor denied the 2009 secret report, Gilligan said, and AT&T’s report only pertains to legal court orders received under the Foreign Intelligence Surveillance Act.

The government has argued that upstream data collection by the NSA is legal under the Foreign Intelligence Surveillance Act.

The judge also asked whether the government was seeking an easy out by simply saying its data filtering was “automatic.”

“It’s concerning that, given the digital age, if the government can’t do something directly, but can do it by a machine, does that open the door to get around whether there was illegal search and seizure?” he said.