After Rep. Devin Nunes failed last summer to force Twitter to unmask several accounts dedicated to ruthlessly mocking the California Republican, the Justice Department took aim at one of the congressman’s anonymous critics.

Court filings unsealed this week revealed that in the last months of the Trump presidency, the Justice Department used a grand jury subpoena to demand the identity of whoever was behind @NunesAlt, a Twitter account that criticized Nunes, a close ally of former president Donald Trump.

Twitter strongly objected to the November request and filed a motion to quash it, noting Nunes’s own failed legal efforts to reveal the identities of his Twitter detractors.

“Congressman Nunes had previously and unsuccessfully attempted, in several ways, to obtain information about his critics,” a lawyer for Twitter said in court documents. “Twitter was concerned that the Subpoena was merely another attempt by Congressman Nunes to do the same.”

In the end, the DOJ’s request was withdrawn after President Biden took office, the New York Times reported Monday.

The subpoena is the latest turn in a years-long legal beef between Nunes and several Twitter accounts with names like “Devin Nunes’ Cow” and “Devin Nunes’ Mom.” The congressman attempted to sue the owners of those accounts and Twitter itself for defamation in 2019, claiming that the nameless critics had tried to “intimidate” him and “intended to generate and proliferate false and defamatory statements.”

Rep. Devin Nunes (R-Calif.) has filed a $250 million defamation lawsuit against Twitter March 18, 2019. (Taylor Turner/The Washington Post)

Nunes, who has a penchant for litigation, is far from the only politician to complain about trolls and critics attacking him online. Other conservatives, including Trump, have long bemoaned a perceived bias against right-wing politicians on social media platforms.

But Nunes’s efforts to find those responsible for biting tweets calling him a “treasonous cowpoke” and “udder-ly worthless” have often backfired by propelling those accounts to viral success. While “Devin Nunes’ Cow” had a mere 1,000 followers when the congressman took aim at the account, today it has more than 770,000. @NunesAlt, the account targeted by the DOJ, now has more than 121,000 followers.

A Virginia judge tossed his defamation case against Twitter last summer, citing a law that protects social media companies from being held liable for content posted to their websites.

About five months later, the Justice Department stepped in with its grand jury subpoena, arguing that it needed to identify the person behind the @NunesAlt account because of a criminal investigation that involved “threatening communications in interstate commerce.”

The request was made under the leadership of Michael R. Sherwin, who had been appointed by Attorney General William P. Barr as acting U.S. attorney for the District of Columbia. The Justice Department also filed a gag order that prevented Twitter from speaking publicly about the case.

Twitter reviewed the @NunesAlt account and found that it was “devoted entirely to political parody” and had a large audience, suggesting that the owner of the account was using the “First Amendment right to anonymously criticize a politician.”

The company also argued that the DOJ should have to prove that the government had found evidence of a threat made by the account before the court ordered Twitter to reveal the user’s identity. When a lawyer for Twitter asked for examples of threats posted by the account, though, the government demurred.

“I have consulted with my supervisor here at the US Attorney’s Office, and we will not agree to provide any further information at this time,” a DOJ lawyer said in an email exchange with Twitter’s legal team in January, according to court records. The subpoena asked Twitter to provide the requested information to a Capitol Police official or during a grand jury hearing.

The Times reported that the DOJ withdrew the subpoena this spring. The Justice Department did not return a request for comment from The Washington Post late on Monday.

The anonymous critic behind the @NunesAlt account, which calls itself “Devin Nunes’ Alt-Mom,” reacted with dismay after the court records were unsealed.

“There’s nothing remarkable about me,” @NunesAlt said in a tweet. “I’m a basic smarta-- with a Twitter account. So then why am I being sued by a US congressman?”

The Twitter user suggested that the government’s campaign to unmask Nunes’s Internet foe threatened anyone who dared to speak out anonymously against politicians.

“Why would the DOJ ever target me? Is it the mean tweets and bad memes?” @NunesAlt tweeted Monday. “It’s not about me or this silly account. It’s about silencing all of us.”