Q: What is unmasking?

A: In the course of lawfully monitoring foreigners, U.S. intelligence agencies sometimes intercept the communications of U.S. persons — citizens and lawful permanent residents. Those individuals are identified anonymously in intelligence reports, usually by a moniker such as “U.S. Person 1,” to protect their privacy and civil liberties.

When a senior U.S. official has a demonstrable need to know who U.S. Person 1 is, he can make a request to “unmask,” or reveal, that person’s true identity.

Q: Is unmaking improper?

A: Not if it is done for a reason and according to the rules. Officials make thousands of unmasking requests every year. The routine process is used to identify potential terrorists and spies, as well as to warn Americans or U.S. companies who might be targeted by hostile governments. Sometimes, an intelligence agency has not intercepted a U.S. person’s communications but has overheard a foreign government talking about that person. In that case, the person’s name is also “masked.”

Only senior officials can request unmasking, and each request is reviewed by officials at the agency that generated the intelligence report. Usually, that is the National Security Agency, which conducts electronic surveillance of foreign people and organizations. A U.S. official has to possess or demonstrate a “need to know” the U.S. person’s name. For example, if a U.S. person were communicating with a known foreign spy, the director of the FBI or a senior counterintelligence official would probably have a need to know that fact and could request the unmasking.

Q: Did all of the officials identified in a recently declassified document request to unmask Michael Flynn? And were their requests because of his calls with Sergey Kislyak, then Russia’s ambassador to the United States?

A: Probably not. For starters, the U.S. officials who made the unmasking requests may not have known “U.S. Person 1” was actually Flynn. It is more likely that they learned some U.S. person was communicating with Russian officials in a concerning way, and then requested to know who the person was. Not all of the Obama-era officials whose names were released may have made the request or even seen the unmasked information. It is possible another official may have made the request and said they should see the information.

It is also unlikely that these requests were all about Flynn’s calls with Kislyak, because many of them predate those conversations, which took place in late December 2016. That raises questions about what other events or information concerned these U.S. officials and prompted them to make unmasking requests.

Q: Vice President Joe Biden made an unmasking request on Jan. 12, 2017. Why would he have done that?

A: That is not clear yet. Jan. 12 was the day that The Washington Post first reported that Flynn, then the national security adviser-designate for the incoming Trump administration, had phoned Kislyak several times on Dec. 29, the day the Obama administration announced the expulsion of 35 Russian officials as well as other measures in retaliation for Russia’s interference in the 2016 election. Biden was the vice president and a senior official involved in the Obama administration’s foreign policy and the transition, so he would probably have a need to know about those calls.

Biden also might not have made the request himself. Some staff are allowed to request unmasking on their boss’s behalf, either at his request or in anticipation that the official will want and need to know the information, according to people who have been involved in the unmasking process.

Q: Does the Trump administration also unmask U.S. persons’ names?

A: Yes, and in large numbers. In 2018, the NSA, which does most unmasking, revealed the identities of 16,721 U.S. persons, according to the Office of the Director of National Intelligence. That was a more than a 7,000-person increase from 2017.

This does not mean the requests were improper. It may reflect an increase in the number of people or American businesses being victimized by a foreign government, including through computer hacks, and whose identities were revealed to warn them, a U.S. official said when the numbers were first published last year.

In 2019, the NSA unmasked 10,012 U.S. persons. That was a significant decrease, but it was still more than the number from the final year of the Obama administration.