Montana has become the first state to ban TikTok, setting up a possible legal battle that could affect the fate of the popular social media app in the U.S.

The ban, slated to take effect on Jan. 1, is considered the most drastic measure any state has taken against TikTok. Many cybersecurity experts have questioned whether Montana can effectively implement something so new and complex.

Gov. Greg Gianforte signed the bill, Senate Bill 419 on Wednesday, saying it is intended to safeguard the data of Montana residents from the Chinese government, echoing theoretical fears that officials in the White House have with the hit video app.

TikTok is owned by Beijing-based tech giant ByteDance. For years, national security experts in Washington have been wary about the app's growing popularity in the U.S., citing intelligence laws in China that provide the government unfettered access to company records. Yet there is no public evidence that Chinese officials have ever sought TikTok user data.

How will the ban work?

Under the Montana law, tech companies, not everyday users of TikTok, could be penalized. For instance, Apple and Google, which operate app stores on phones and devices, could be subjected to fines up to $10,000 a day for letting people download TikTok.

Representatives from Apple and Google have not commented on the law, but cybersecurity experts say there are a few ways the companies could comply.

Apple and Google could block TikTok from all accounts that have billing addresses in Montana, said Roger Entner, a telecoms analyst at Recon Analytics.

Entner said the companies could also prevent all IP addresses located within Montana's borders from being able to download TikTok from app stores.

"If they can prevent you in China from accessing Google, that's the same thing," Entner said. "So of course Apple and Google can prevent Montana residents from accessing TikTok."

That said, there would be loopholes, like using a virtual private network, or VPN, a service that can be used to sidestep internet restrictions, Entner said.

"The ban gets tricky. If you're near a state border, and your phone pings a cell phone tower inside of Montana, it might look like you're in Montana when you're not," he said. "The ban could hit many people who shouldn't be affected."

TikTok expected to launch a legal fight

TikTok is expected to fight the law in court.

Groups including the ACLU support it challenging the law, which they cast as a violation of the First Amendment.

"The government cannot impose a total ban on a communications platform like TikTok unless it is necessary to prevent extremely serious, immediate harm to national security," the ACLU said in a statement. "But there's no public evidence of harm that would meet the high bar set by the U.S. and Montana Constitutions, and a total ban would not be the only option for addressing such harm if it did exist."

Legal experts say that, while the First Amendment does protect free expression on TikTok, the government can restrict speech if there there is a risk to national security, such as if online speech is providing support to terrorists. Far less certain is whether the perceived danger TikTok poses to national security would override the free speech protections.

Digital rights groups, including the Electronic Frontier Foundation, do not see TikTok as a national security risk and are sounding the alarm about the Montana law.

"This unconstitutional ban undermines the free speech and association of Montana TikTok users and intrudes on TikTok's interest in disseminating its users' videos," the organization said in a statement. "It is a blatant violation of the First Amendment, whether it's done by Congress or Montana. This ban won't protect Montana residents' private data. Companies will continue to harvest and monetize personal info and make it widely available to purchasers, thieves, and foreign actors."

Last December, Gianforte banned TikTok on state government electronic devices.

On Wednesday, he added that the ban would expand to include "all social media applications that collect and provide users' personal information or data to a foreign adversary, or a person or entity located within a country designated as a foreign adversary," including the popular messaging app, WeChat, which is owned by China-based Tencent.

Montana's legal fight with TikTok could influence White House decision

President Biden signed legislation banning the app from government devices last December, and has been considering an all-out ban if TikTok's parent company ByteDance, cannot find an American buyer.

TikTok, for its part, has invested $1.5 billion into a data security plan known as "Project Texas," that the company says will cordon off all of Americans' data from China.

But the Biden administration has not been satisfied with the proposal, since it falls short of ByteDance selling off TikTok to an American tech company, or a group of investors outside of China.

Negotiations over the future of TikTok have reached a standstill in the White House, even as China hawks close to Biden continue to push for an outright national ban of TikTok.

Now, the first legal test of such a ban will likely pit Montana state officials against TikTok, the outcome of which could inform the next steps the White House takes.