Sen. Lindsey O. Graham (R-S.C.), pictured at the U.S. Capitol, asked a panel of intelligence officials whether his communications had been intercepted when he talked to foreign officials abroad. (J. Scott Applewhite/Associated PRess)

The intelligence community is seeking permanent authority for a contested surveillance program at a time when senators in both parties are increasingly frustrated in their attempts to learn how much information spy agencies collect on American citizens — and even on senators themselves.

At a Senate Judiciary Committee hearing Tuesday, Sen. Lindsey O. Graham (R-S.C.) asked a panel of intelligence officials whether his communications had ever been swept up when he was talking to a foreign leader abroad.

“Am I entitled to know?” he demanded. “Am I entitled to know if my communications were collected?”

The officials — from the Office of the Director of National Intelligence (ODNI), the National Security Agency, the FBI and the Justice Department — struggled to answer the senators’ questions, in some cases saying they could better reply in a classified session before the same panel on Wednesday.

At issue is a program authorized by Section 702 of the FISA Amendments Act, a 2008 law that Congress approved after years of acrimonious debate about foreign intelligence collection on U.S. soil without individualized warrants. The law allows the NSA to collect the communications of “non-U.S. persons” — those who are not U.S. citizens, companies and residents — who are outside the United States for foreign intelligence purposes.

Renewal of Section 702, which will expire in December, is the intelligence community’s highest legislative priority this year. And the officials cited several previously undisclosed examples of the value of the program in catching terrorists and thwarting plots.

Carl Ghattas, head of the FBI’s national security branch, said that Section 702 was instrumental in identifying Shawn Parson, an Islamic State member from Trinidad and Tobago, and members of his network.

Parson’s network pushed out “prolific amounts” of English-
language terrorist propaganda, and encouraged followers to carry out attacks in Western Europe and the United States, Ghattas said. Sharing Parson’s contacts with international partners led to the identification of other Islamic State facilitators and potentially prevented attacks in several countries, he said. Parson was killed in Syria in September 2015.

The officials told lawmakers that they would like the law to be made permanent without a need for reauthorization every few years.

But some lawmakers from both parties have concerns about protecting the privacy of U.S. citizens and residents, and some Republicans have used the debate as a platform to suggest — without offering evidence — that Obama administration officials inappropriately handled and then leaked intelligence to harm Trump transition officials.

Sen. Dianne Feinstein (Calif.), the panel’s ranking Democrat, said she would not vote to reauthorize the law without a sunset date. “Technology and communications change, and a sunset allows us to review and revise such as may be necessary,” she said.

A key point of contention was the NSA’s professed inability to produce even a rough estimate of the number of people in the United States whose emails or phone calls are gathered when the NSA is targeting foreigners abroad. A person in the United States cannot be targeted without a warrant, but if the American is communicating with a valid foreign target, his or her calls or emails are collected “incidentally.”

Bradley Brooker, acting general counsel for the ODNI, said the NSA has made “significant efforts” to devise a counting method to come up with a number.

“Unfortunately, we were unable to develop an accurate, meaningful and cost-effective methodology,” he said. He said doing so would mean asking NSA analysts “to conduct intense identity verification research” on people who are not targets. “From a privacy and civil liberties perspective, we find this unpalatable,” he said.

But later in the hearing, Elizabeth Goitein, of New York University School of Law’s Brennan Center for Justice, said that senior intelligence officials in the Obama administration had committed to providing a number in early 2017. “In fact, all accounts, public and private, suggested they were on the verge” of providing it, she said. “We’ve had a change of administration, and the government has now backed off of providing that information.”

Sen. Richard J. Durbin (D-Ill.) chided the officials for saying the agencies have been transparent in their reporting. “How are we supposed to believe we have great transparency if you can’t even identify for us how many Americans have been swept up?” he said.

In his exchange with Graham, Brooker said that he has been working with Graham’s staff to get him an answer to whether his communications were collected. Brooker said that if there is an intelligence report based on an intercept of a foreign official speaking with him, then his identity would be masked.

Would it be possible for someone in the administration to “get a hold of the conversation and unmask” his identity? Graham asked.

If there is a request to unmask a lawmaker’s identity, there is a procedure that requires the relevant agency to seek approval from the ODNI before unmasking, Brooker said. That information generally goes to congressional leaders and the leaders of the intelligence committees, he said.

Julie Tate contributed to this report.