A Republican effort to determine who may have leaked the name of Michael Flynn in connection to his 2016 contact with the Russian ambassador has centered on the question of which Obama administration officials requested his identity be “unmasked” in intelligence documents.

But in the FBI report about the communications between the two men, Flynn’s name was never redacted, former U.S. officials said.

Senate Judiciary Committee Chairman Lindsey O. Graham (R-S.C.) announced this week that he wants to subpoena witnesses over the unmasking of Flynn, as part of a larger effort to unearth information about the FBI’s investigation of Trump campaign officials.

On Tuesday, he sent a letter to acting director of national intelligence Richard Grenell asking why a declassified list of Obama administration officials who had made requests that revealed Flynn’s name in intelligence documents “did not contain a record showing who unmasked” Flynn’s identity in relation to “his phone call with” the Russian diplomat, Sergey Kislyak.

Flynn’s Dec. 29 phone calls with Kislyak became a major controversy. The Washington Post revealed their existence and then that he had misled the vice president about the nature of his discussions with the Russian diplomat. He resigned as President Trump’s national security adviser shortly after the revelations and later pleaded guilty to lying to the FBI about the call, though the Justice Department is now seeking to drop the case.

Trump allies ever since have been pressing to know who leaked information about the call.

The list released last week was declassified by Grenell and provided to GOP senators who wanted to know who requested the “unmasking” of identities in intelligence reports in the last months of the Obama administration that resulted in the name of Flynn being disclosed.

Unmasking is a routine practice used to identify U.S. individuals who are referred to anonymously in an intelligence document, and it is meant to help government officials better understand what they are reading. But conservatives have long seized on Flynn’s unmasking to imply that he was treated unfairly by U.S. law enforcement and intelligence officials.

The list, prepared at Grenell’s request by the National Security Agency, covered requests made between Nov. 30, 2016 and Jan. 12, 2017. The majority of requests occurred before Flynn’s communications with Kislyak on Dec. 29.

It was the FBI, not the NSA, that wiretapped Kislyak’s calls and created the summary and transcript, the former officials said.

“When the FBI circulated [the report], they included Flynn’s name from the beginning” because it was essential to understanding its significance, said a former senior U.S. official, who spoke on the condition of anonymity to describe sensitive intelligence. “There were therefore no requests for the unmasking of that information.”

When told by The Post that the name was never masked in the Dec. 29 communication, a Graham aide said the committee would still like the Office of the Director of National Intelligence’s “written answer” to its question.

The unmasking issue appears to be part of an effort by the president and his allies to tar former president Barack Obama with what Trump says was an unfounded criminal investigation into potential conspiracy between Russia and Trump associates — or what he now calls “Obamagate.” Obama is expected to be one of the most effective advocates for his former vice president, Joe Biden, in his bid to unseat Trump this fall.

The president’s allies are casting the unmasking requests as evidence of a malign effort to damage Trump through leaks to the media.

“They were unmasking anyone and everyone so that they could leak information to a press that was willing to take that illegal information to build a fake, phony narrative, to set up numerous people on the Trump team, not just General Flynn,” Rep. Devin Nunes (Calif.), the ranking Republican on the House Intelligence Committee, told Fox News last week.

Some analysts, however, say the controversy is contrived.

“This is apparently an effort to confuse the public by conflating routine and legitimate actions of unmasking Americans’ identities for intelligence purposes with the action of leaking classified information to the media,” said Ryan Goodman, a New York University law professor and co-editor in chief of the Just Security blog. “The timing of this effort, over three years since the leak happened, also suggests law enforcement and intelligence agencies are being used for political purposes during the election season.”

After the list was released last Wednesday, Sens. Ron Johnson (R-Wis.) and Charles E. Grassley (R-Iowa) trumpeted the inclusion of Biden, who requested an unmasking on Jan. 12, 2017.

Grenell’s move amounts to “selective declassification” for political purposes, said Sen. Mark R. Warner (D-Va.) in a letter to the DNI on Wednesday. He asked that “in order to more fully and properly inform the American people,” Grenell declassify and make publicly available “any intelligence report concerning conversations” between Flynn and Kislyak.

In that Dec. 29 call with Kislyak, Flynn discussed a set of sanctions ordered earlier that day by the Obama administration in response to Moscow’s interference in the 2016 presidential election. Flynn urged that the Kremlin refrain from retaliating, suggesting the new administration would be more accommodating.

In mid-January 2017, Washington Post columnist David Ignatius revealed that Flynn called Kislyak several times on Dec. 29 and raised the question of whether sanctions came up. A few days later, Vice President Pence on national television said the timing of the call was “strictly coincidental” and that Flynn had assured him the two had not discussed sanctions. Later that month, in an interview with the FBI, Flynn again insisted he and Kislyak never talked about the Obama administration’s censure of Moscow.

In early February, The Post revealed that Flynn had in fact discussed sanctions with Kislyak, kicking up a furor that led to his resignation. In December 2017, Flynn pleaded guilty to lying to the FBI; the Justice Department now is seeking to drop the case against him.

The president’s GOP allies, including his probable next DNI, Rep. John Ratcliffe (R-Tex.), have long pressed to learn who provided the media with information on Flynn’s calls. “It does appear that there were crimes committed during the Obama administration,” Ratcliffe told Fox News last July. “His phone call with the Russian ambassador was a highly classified NSA intercept,” he said, apparently not realizing it was an FBI intercept. “Someone in the Obama administration leaked that call to The Washington Post. That’s a felony.”