The US supreme court surprisingly decided, this week, to hear TikTok’s emergency appeal to its imminent ban in the United States. It may be the most important case at the intersection of the first amendment and national security in decades. Whether or not you see China as a nefarious threat, all Americans who care about free expression should worry about the precedent this case could set – and should want the TikTok ban overturned.

After a fifth circuit court of appeals ruling earlier this month, TikTok’s owner, ByteDance, has until 19 January to either sell the popular video-sharing app or face a nationwide ban. The decision stems from Congress passing a law last year that essentially proclaims that if the government says a foreign-owned platform threatens national security, then it can force its sale or censor it.

The US’s core argument is that ByteDance might be handing over user data to the Chinese government. The US government’s briefs are full of redactions that they’ve not yet shared with the public, despite their unprecedented position that an app used by more than half the country should be permanently made illegal. Officials have publicly admitted that the US position is based on speculation about what China could do, not facts about what it actually does.

Now, no one argues that it’s not possible that the Chinese government is accessing user data. As someone who has advocated for privacy for more than a decade, we should be much more aware about the information any app is giving any party. What is often lost in this debate is that TikTok collects similar or the same type of data that every other app on our phone does. This data is often packaged and sold to third parties, which the Chinese government probably purchases in bulk anyway. That includes data collected by American apps.

It’s hard to believe the US government actually cares about Americans’ privacy, when it also engages in this nefarious practice itself. If Congress were truly worried about Americans’ privacy, they could pass something like the Fourth Amendment Is Not for Sale Act, which would essentially ban companies from selling data to the US government without a warrant, where there is a much more direct line to abuse.

The bigger issue here is that lawmakers are using privacy as a shield to hide their true motivations. If you listen to their own words, this isn’t just about China. In fact, the main impetus for passing this bill might be the Israel-Gaza war. Proposals to ban TikTok were around before the war started – and had significant support – but never got off the ground.

Several of the law’s biggest proponents in Congress have openly expressed how they wanted to shut down TikTok specifically because Americans who use the platform are condemning Israel’s war in Gaza, potentially affecting public opinion at large. Every day there are countless new videos of the death and destruction carried out with US weapons by its closest ally. The fifth circuit conveniently ignored these stated motivations, despite the Knight First Amendment Institute at Columbia University comprehensively cataloging them in a legal brief.

Historically, the US supreme court has deferred to prosecutors to a depressing extreme when they make secret “national security” claims related to information the government holds – whether it’s the oft-abused state secrets privilege, the prosecution of journalists’ sources or mass-surveillance capabilities. Thankfully, when the first amendment rights of ordinary Americans are at stake, the court has traditionally been more skeptical.

In one of the most famous first amendment cases of the 20th century, the supreme court ruled in the Pentagon papers case that the Nixon administration couldn’t censor the New York Times from publishing leaked documents just because the government claimed that national security could be harmed. Justice Hugo Black famously wrote: “The word ‘security’ is a broad, vague generality whose contours should not be invoked to abrogate the fundamental law embodied in the First Amendment.”

Nowhere in the fifth circuit’s decision does the court cite or even try to distinguish the TikTok case from that decision – they just completely ignore it.

Likewise, the supreme court has also ruled that Americans have the right to consume foreign propaganda if they so choose. In that case, the “foreign propaganda” is much more direct – created and distributed from foreign soil – not Americans expressing their own opinions on a platform that’s not directing them to say anything.

In the age of misinformation and foreign influence operations, this first amendment right may seem more controversial to some. It’s important to point out that no free-expression advocate will argue that propaganda, whether true or not, is a wholly good thing. But the free flow of information – good and bad – is exactly what separates us from countries like China, which tightly restrict what its citizens can and can’t see.

The US government has long decried the Chinese government’s insistence on banning apps and websites because they originate in the United States. Rather than stand on our values, its response in this case has essentially been: Let’s be more like China.

There is an alternative that would diminish the influence of propagandists without abandoning our values: cutting down on government secrecy and hypocrisy (not to mention the bankrolling of atrocities), which breeds distrust and leads young people to look elsewhere for information.

It’s possible the supreme court could essentially re-affirm its past precedents upholding the first amendment – worryingly, it also could move to weaken or overturn them. That would create a dangerous scenario where the Trump administration could abuse the TikTok law to ban other communications platforms that originated internationally. It could also throw away other long-held first amendment rights with it, affecting publishers, journalists and countless sources of news consumed by Americans.

Trump has done a 180 on his previous position on TikTok. It was his first administration that first attempted to ban the app; he now says he’ll attempt to reverse the ban, though legal experts say he has limited options. Regardless of what he can or can’t do in this case, it is yet another in a long line of laws that Democrats have supported that could hand Trump extraordinary power to potentially abuse in the future.

Let’s hope the supreme court does the right thing and strikes down this dangerous grant of censorship power before it spins out of control.

• Trevor Timm is executive director of the Freedom of the Press Foundation