Can you still use TikTok if it’s banned? What users should know about the app.

Lawmakers’ months-long battle to ban the social media app TikTok in the United States came to a head on Friday when the Supreme Court upheld a law that determined the app’s fate for its 170 million American users.

TikTok, owned by Chinese company ByteDance, now faces a ban on January 19, and here’s what users can expect to happen:

No. The law passed by Congress last year would make it illegal for app stores from companies like Apple and Google to distribute or issue updates to TikTok, risking hefty civil penalties: $5,000 per US user, which could amount to hundreds of billions of dollars.

If TikTok gets banned, it will likely disappear from app stores overnight. (Apple and Google have not commented on their plans to remove the app.)

Apple has long complied with foreign governments that have ordered apps to be removed in their countries. Last April, for example, Apple pulled communication apps such as WhatsApp, Signal, Threads and Telegram from its app store in China at the request of the Chinese government.

Yes. The law does not make it illegal to have the TikTok app on your phone.

“The letter of the law is about future downloads and updates,” said Dean Ball, a researcher at the Mercatus Center, a George Mason University think tank. “It’s not about removing the app from people’s phones.”

But without ByteDance’s ability to issue updates to TikTok via app stores, the app is likely to deteriorate over time. Still, advertisers expect some use in the U.S. after the ban, and as of last month new contracts to advertise on the app were still being signed, said Craig Atkinson, CEO of Code3, a digital marketing agency.

TikTok can also intervene before the app degrades and block its US users from accessing videos on the platform after January 19.

In India, which banned TikTok in 2020, users of the app are met with a screen that says “Service not available” and blocks users from its platform.

TikTok has not said whether it will restrict access to the app if it is banned, and it did not respond to a request for comment.

No. In addition to banning app stores from hosting the app, the law applies to internet hosting companies.

Users will likely still be able to access TikTok if they use a virtual private network, or VPN, which encrypts a user’s location.

The ban “could even be a big business boost for VPN providers,” Mr. Atkinson.

Some experts believe it is possible that Apple and Google may decide not to comply with the law, betting that President-elect Donald J. Trump, who has come out in support of TikTok, would order his attorney general not to to enforce the ban.

“But unless there’s some new information being added to the equation, I’d be very surprised if Apple and Google did that,” Mr. Ball.

Mr. Trump could also change his mind or even use the threat to enforce the law as leverage against the two companies, said JB Ferguson, a managing director at technology-focused Capstone.

“I don’t know that you’re adequately defending shareholder value if you don’t take the law seriously, even if you believe in Trump,” Mr. Ferguson on Apple and Google.

Mr. Trump has also considered signing an executive order that could effectively neutralize the law.