TikTok and its Chinese parent company ByteDance have filed a lawsuit challenging a new law that United States President Joe Biden signed last month to force the sale or ban of the popular video-sharing app in his country, saying the legislation violates the First Amendment rights of US citizens.

"For the first time in history, the Congress has enacted a law that subjects a single, named speech platform to a permanent, nationwide ban, and bars every American from participating in a unique online community with more than 1 billion people worldwide," TikTok and ByteDance said on Tuesday in a petition filed in the US Court of Appeals for the District of Columbia Circuit.

Banning TikTok is so "obviously unconstitutional", and the new law leaves TikTok with no choice but to shut down by Jan 19 as continuing to operate in the US wouldn't be commercially, technologically or legally possible, they said.

It will silence the 170 million US people who use the platform to communicate in ways that cannot be replicated elsewhere, they said.

The law, which was signed by Biden on April 24, requires ByteDance to divest TikTok within nine months or face a ban in the US, with a possible three-month extension if a sale is in progress.

The companies said in their petition it's impossible to transfer the platform's "millions of lines" of code to a new owner, and that the app will not sell its recommendation algorithm.

Declaratory judgment

They argued that they should be protected by the First Amendment's guarantee of freedom of expression and are seeking a declaratory judgment that the law is unconstitutional.

Moreover, Congress itself has offered nothing to suggest the Tik-Tok platform poses the types of risk to data security or the spread of foreign propaganda that could conceivably justify the law and has failed to prove the app poses any specific harm in these areas, they said.

ByteDance has insisted it has no intention of selling TikTok. The White House has said it wants to see Chinese-based ownership ended on "national security grounds".

Jameel Jaffer, executive director of the Knight First Amendment Institute at Columbia University, said TikTok's challenge of the ban is important, expecting TikTok's lawsuit to succeed.

"The First Amendment means the government can't restrict Americans' access to ideas, information, or media from abroad without a very good reason for it — and no such reason exists here," Jaffer said in a statement.

"Anything that the US government does not like becomes a threat to national security. It's an overall excuse to cover everything. Simply by calling it a 'national security' issue, they feel that they can justify taking any action whatsoever," George Koo, a retired international business adviser in Silicon Valley, California, told China Daily.

"For TikTok to take on the US government at the US court system is very much the last measure and whether they will get a fair hearing and fair justice remains to be seen. But I wouldn't be surprised if TikTok fails in the lawsuit," he said.

"I think if TikTok is forced to divest the Chinese ownership, they (will have) to just leave the US altogether.… That will be a very unpopular move for the young people, for the 170 million fans of TikTok," Koo said.

TikTok filed a lawsuit against Montana in May 2023 when it issued a similar ban. Last November, a federal judge ruled in favor of TikTok and blocked the law before it took effect.

Lia Zhu in San Francisco contributed to this story.

Contact the writers at [email protected].