TikTok’s expected legal challenge to a law signed Wednesday by President Joe Biden forcing the popular app’s parent company to spin off its US operations could be a seminal moment in First Amendment law in what is shaping up to be a year of defining cases.

The new law gives TikTok’s parent company ByteDance nine months to sell the short-form video app or face a ban in the US, where it claims some 170 million users and has raised national security concerns over its ability to potentially gather data on and influence Americans.

But in an ironic twist, ByteDance, which is based in China where the ruling Communist Party has cracked down on free speech and dissent, will be relying on this very American right to protect its business interest.

“We are confident and we will keep fighting for your rights in the courts. The facts and the Constitution are on our side and we expect to prevail,” TikTok chief executive Shou Chew said in a video posted on the app in response to the new law.

In recent months, the company has foreshowed it plans to challenge the law on First Amendment grounds. In the run up to the law’s passage, TikTok encouraged its millions of users to call members of Congress to protest the bill, arguing it would infringe on “their Constitutional right to free expression.”

Last year, a federal judge halted a first-of-its-kind statewide ban on TikTok in Montana, stating the law had “both harmed [TikTok’s] First Amendment rights and cut off a stream of income on which many rely.”

Although the details of TikTok’s legal case are not yet public, legal scholars say the government only has a very narrow argument to stand on to force the sale.

“At stake here is not TikTok’s interests, but the interests of the millions of Americans who use the platform,” Ramya Krishnan, a senior staff attorney at the Knight First Amendment Institute at Columbia University, told CNN. “So whatever rights TikTok has or does not have, it is indisputable that Americans have a right to access and use social media and media of their choosing.”

To overcome that right, the government’s strongest argument is based on national security, said Nate Persily, Stanford law professor and Founding Co-Director of the Stanford Cyber Policy Center.

“If the company is acquiring data on the US population that can be used by the Chinese government in a way that threatens American national security, that of course is a compelling state interest that could overwhelm of what might be the first amendment rights of the users or the platform,” Persily said.

“I think that’s a pretty solid argument, actually. I mean, is it even technically feasible to wall off their data gathering operations in the US, given that they it feeds back into the algorithm globally right now,” Persily added.

FBI Director Christopher Wray said earlier this week that TikTok is “a national security concern” because “it is beholden to the Chinese government.”

“It has to do with the data, the recommendation algorithm, and the software,” Wray said in an NBC News interview. “The data, we’re talking about the ability to control or collect data on millions and millions of users, and to use it for all sorts of influence operations, like driving their AI efforts which are not remotely constrained by the rule of law.”

TikTok says it has never provided data to the Chinese government and has “invested billions of dollars to keep US data safe and our platform free from outside influence and manipulation.”

But legal experts say potential influence operations on TikTok, such as suppressing content on the app, is not a persuasive argument that will stand up in court. (TikTok has denied it suppresses content).

“It’s less persuasive to say that the reason you’re going to ban the foreign platform is because you’re afraid of the messages that it communicates,” Persily said.

Krishnan said even the national security argument will not withstand legal scrutiny because the Chinese government could easily purchase the same data on Americans through the open market.

“[The government is] not going to be able to satisfy that burden here, not only because much of this information is information that China could obtain through other means, but because the government could much more effectively protect American privacy by passing a comprehensive data privacy law,” she said.

TikTok’s looming legal challenge will be one of several that could eventually reach the US Supreme Court that could completely redefine online speech. Other high-profile cases that will determine whether social media companies can moderate content on their platforms are also likely to be decided this year.

“The rules for online speech are being written by the Supreme Court this year,” Persily said.

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