In a case that could crack the foundation of online freedom, Judge Diane J. Humetewa of the U.S. District Court for the District of Arizona ruled that the U.S Department of Justice (DOJ) can force a private company like Facebook, Yelp, or Twitter, to give up your identity simply because you expressed an opinion online.

This ruling occurred after the U.S Department of Justice (DOJ) obtained a grand jury subpoena to make Glassdoor, an online job-review website, hand over the identities of eight people (the DOJ initially wanted 125 individuals’ IDs). The DOJ wanted their internet protocol (IP) addresses, credit card information, and other personal details so it could question these individuals and perhaps compel them to testify against a company under a DOJ fraud investigation.

So while Glassdoor boasts that they’ve “succeeded in protecting the anonymity of our members in more than 80 (civil suits)” by companies ticked off about something someone posted anonymously, this is a criminal case related to an unknown private company, and as they say, a different kettle of fish altogether.

Now, while one might be sympathetic with the feds’ need to do their job, forcing a private company to essentially ‘unmask’ the identities of its users would set a dangerous precedent—allowing Big Brother-style intrusions anytime the government wants to know who said what.

Glassdoor tried to avoid this constitutional fight by offering instead to post a notice on its site asking people to come forward to give information. Glassdoor has done that before. But that wasn’t enough for the DOJ.

To parry this attempt to unmask private citizens, Glassdoor, a California-based company, appealed the ruling to the Ninth Circuit Court of Appeals.

So this has become a constitutional fight. If this ruling stands then any comment you make on Facebook, Twitter or a review at Yelp could give the federal government the power to find out your real identity—even if you aren’t accused of committing a crime. Your personal information might then go public, as it could be available via a Freedom of Information Action (FOIA) request or other means, to your employer and anyone else. In such an environment, would members of a labor union pause before freely expressing their views to one another? Would a whistleblower decide not to give information “anonymously” because they might be exposed?

“We’d like a precedent set that respects American freedom in today’s world. The government is arguing they should be able to find out someone’s identity as long as it is not acting in ‘bad faith.’ We’re arguing that, legally speaking, the government is required to pass a ‘compelling interest’ test before being given the authority to demand people’s identities from a private company,” said Brad Serwin, general counsel at Glassdoor.

“We believe the lower court applied the wrong standard in placing the interests of government ahead of Americans’ protected free speech rights under the First Amendment. We hope to persuade the U.S. Ninth Circuit Court of Appeals to require a higher standard for these requests.”

Fourth Amendment protections don’t block this because the government is going after a private company (a third party) for this information, so, according to the Supreme Court’s established “third-party doctrine,” these people have “no reasonable expectation of privacy.” So yes, according to this judge, all those pseudonyms we see on social media and in comment sections below articles are no protection from snooping Big Brother if the government wants to know who is speaking anonymously.

Whatever the outcome of the appeal to the Ninth Circuit, the Supreme Court should weigh in eventually, as the legal precedents being cited in this case are old (before the internet age) and unclear. Glassdoor argues the Ninth Circuit should apply a “compelling/substantial connection test” from Bursey v. United States, a 1972 decision that involved members of the Black Panthers who were held in contempt after they refused to answer questions from a federal grand jury. The government, meanwhile, thinks that the test in Branzburg v. Hayes, a 1972 Supreme Court case that invalidated the use of the First Amendment as a defense for reporters summoned to testify before a grand jury, makes their case.

Outside of the constitutionally protected rights being affected here, there is a more practical reason for Glassdoor—and for any website that allows online reviews or comments—to fight such a ruling: It undermines their business model. Right now Glassdoor allows individuals to post incognito reviews of employers, which gives other people information about an employer they might be considering a job offer from. Glassdoor says it gets about 45 million unique visitors every month. But how many people would post a critical review of a current or former employer if they thought the government might reveal their identity, not because of any criminal fault of their own, but because the government has an interest compelling it to force them into the public light?

Maybe this Arizona judge is simply an outlier, as other judges have ruled differently on similar cases. In SunEnergy1, LLC, et al. v. Jeffrey Lawrence Brown, for example, the court ruled: “The content of the reviews on Glassdoor.com are such that it should be obvious to any reasonable person that the authors (all listed as current or former employees) are using the website as a vehicle to express their personal opinions about the company in question. Glassdoor.com is a website for employment and company evaluation—it is not a news website (e.g. WSJ.com or NYT.com) where there is an expectation of objective reporting and journalistic standards.”

Meanwhile, two organizations have already thrown their support behind Glassdoor’s fight for online privacy. Media Alliance, a media-advocacy group, said, “Anonymous online expression is a key tenet for many of our civil rights including labor organizing, political dissent and artistic freedom. Individuals should not have to fear the government will compel the disclosure of their identities from the platform of their choice without their consent when they have committed no crime.”

TechFreedom, a tech-advocacy group, said, “The government’s argument presumes there’s something nefarious about posting online anonymously. That’s absurd. People use sites like Glassdoor in order to speak candidly about their employers and provide valuable information to other inquiring users. They’re effectively the whistleblowers of the workplace. No one’s saying that law enforcement shouldn’t be able to unmask them—only that they should have to provide some showing of the need to do so.”

This isn’t a partisan issue. Both sides of the political spectrum understand that allowing the government to attain someone’s personal identity simply because they chose to speak anonymously online would surely chill speech.

Frank Miniter is the author of Kill Big Brother, a novel that shows how we can keep our freedom in this digital age.