The attempt to unmask a critical Twitter account was an affront to our fundamental right to anonymous expression.

For a few weeks, the government seemed to forget that the Constitution protects the right to speak anonymously. Thankfully, the prospect of a legal challenge from Twitter and the ACLU appears to have jogged its memory.

On March 14, U.S. Customs and Border Protection sent Twitter a demand for information that could unmask the user behind the @ALT_uscis Twitter account, which is run by an anonymous speaker critical of the government’s immigration policies. Oddly, CBP issued the summons under the Tariff Act of 1930, a statute intended only for inquiries related to the trade of merchandise. The government’s demand seems to have been motivated by a desire to stifle the content of the tweets.

The First Amendment prohibits government attempts to unmask a speaker simply because it disagrees with him or her. Constitutional strike one.

And CBP sought not only identifying information about the user — including the account’s login information, phone number, mailing address, and IP address — but also “[a]ll information regarding” the account. Such a request, which could sweep in private direct messages and other sensitive information, violates not just the First but also the Fourth Amendment. Constitutional strike two.

Recognizing the demand for what it was — unlawful and illegitimate government overreach — Twitter filed a lawsuit last week asking the court to nullify the summons and declare it unconstitutional and unenforceable. We represented the user and intended to file in the case on the user’s behalf. But less than 24 hours after Twitter filed, CBP buckled and withdrew the summons. As a result, Twitter dismissed the suit and the @ALT_ uscis user is able to continue speaking, free from the specter of government interference.

The ability of @ALT_uscis to tweet anonymously is incredibly important, both to the user and to a free society. Anonymity plays a central — and constitutionally protected — role in the time-honored tradition of advocacy and dissent. Our founding fathers authored the Federalist Papers as “Publius” (and heard from “the Federal Farmer” in response). That means that the drafters of the Constitution themselves relied on pseudonyms to express views on the central political issues of their day. So it is no surprise that the Supreme Court has recognized time and again that the right to speak freely necessarily includes the right to speak anonymously, which empowers individuals who otherwise might not feel free to speak out against the majority to criticize the government or to mobilize for change.

This free speech right is as important today as ever. The @ALT_uscis user relies on the ability to speak anonymously when sharing public information with the account’s tens of thousands of followers, and when expressing views that are critical of the government. That user isn’t alone — in the aftermath of President Trump’s inauguration, many “alt” accounts criticizing various government agencies were created. The government can no more erase them from existence than it can do away with the First Amendment, and its attempt in this case probably didn’t go quite as planned: When word of the suit got out, the number of @ALT_ uscis’ Twitter followers jumped from 32,000 to 192,000 today. Censorship has a way of piquing the public’s interest.

Using a pseudonym enables the user behind @ALT_uscis to speak without fear of personal attacks and harassment, and without having to worry about being targeted for investigation based on the content of the tweets. Now out from under a government summons seeking to unmask the account, the user can fully enjoy that freedom again.

We are thankful that Twitter stood up for the rights of the user and took a strong position in defense of the First Amendment. And we appreciate that the government came to its senses this time. We are also ready to respond should it forget again.