The government blinked.
A day after Twitter sued the Department of Homeland Security over an order that would have forced it to reveal who's running an anti-Trump account, the government rescinded its request.
On Friday, Homeland Security dropped its demand, which prompted Twitter to retract its lawsuit. The lawsuit had been filed on Thursday.
"Because the summons is now withdrawn, Twitter voluntary dismisses without prejudice all claims against Defendants in the above-captioned matter," Twitter wrote in a filing.
In the original suit, Twitter said an arm of DHS used a "limited-purpose investigatory tool" in an effort to unmask the identity of the person or people behind @ALT_uscis, an account that criticizes the Trump administration's management of US Citizenship and Immigration Services. USCIS is part of DHS.
According to the suit (PDF), US Customs and Border Protection, also part of DHS, issued a summons on March 14 demanding that Twitter release records that would lead to the account's owners. The company argued the order was unlawful and must be dismissed.
The company declined to comment beyond the lawsuit for this story. DHS declined to comment. The White House didn't respond to a request for comment.
The account, which identifies itself as "immigration resistance," is one of dozens of "alternative" government agency accounts that sprang up after Donald Trump was inaugurated as the country's 45th president. Other alt-accounts include @AltUSNatParkService, which bills itself as "The #Resistance team against #AltFacts#FauxNews #FauxScience," and @RogueNASA, "The unofficial 'Resistance' team of NASA."
Some of those accounts tweeted out support for Twitter and @ALT_uscis as news of the social network's victory spread.
The person or persons behind @ALT_uscis didn't respond to a direct message seeking comment. But the account had earlier pinned a tweet of the First Amendment, which protects free speech, to the top of its page.
In the lawsuit, Twitter had argued that the people behind the anti-Trump accounts, some of whom say they're government employees, risk harassment and retaliation, as well as their jobs, if their real identities are revealed.
Twitter also said in the suit that the summons and the laws behind it don't apply to the social network's users. They are typically issued in cases in which the Customs Service finds something suspicious with merchandise being imported.
The social network accused the US government of violating the First Amendment in an attempt to silence political speech. The @ALT_uscis account was created around the time Trump issued a January order restricting immigration, which was later blocked by courts.
Roy Gutterman, a media law expert at Syracuse University, said the Trump administration's move seems to be an effort to root out critics and appears to violate the First Amendment.
"America has a long history of protecting critics of government, and Twitter is a modern form of expression and criticism," Gutterman said. "In this case, it's even more nefarious because the government is trying to find out who's saying bad things about it because that person or people could very well be working for the government."
On March 14, CBP agent Adam Hoffman sent a fax to Twitter, demanding the website provide the agency with user names, login information, phone numbers, mailing addresses and IP addresses behind the account. The summons threatened further court action if Twitter didn't comply.
The agency also set a deadline of March 13, one day before the summons was actually faxed. It asked that Twitter keep the summons under wraps for "an indefinite period of time."
You can see the summons here:
Twitter notified the @ALT_uscis account owners on April 4, according to the lawsuit.
Before Friday's end to the lawsuit, the American Civil Liberties Union had expressed solidarity with Twitter, indicating it would filed documents in court on the account's behalf.
"To unmask an anonymous speaker online, the government must have a strong justification," ACLU attorney Nathan Freed Wessler said in a statement. "But in this case, the government has given no reason at all, leading to concerns that it is simply trying to stifle dissent."
Twitter has unmasked accounts in the past, as it did earlier this year when helped the FBI catch the Twitter user who sent a seizure-inducing GIF as part of a hate crime.
First published April 6 at 1:09 p.m. PT.
Updated April 6 at 2:01 p.m. PT: Added remarks from the ACLU and more details from Twitter's lawsuit.
Updated 3:59 p.m. PT: Added expert opinion and more detail.
Updated April 7 at 11:27 a.m. PT: Added Twitter had dropped its lawsuit after the DHS retracted its demands.
Life, disrupted: In Europe, millions of refugees are still searching for a safe place to settle. Tech should be part of the solution. But is it? CNET investigates.
Tech Enabled: CNET chronicles tech's role in providing new kinds of accessibility.