The president-elect backed TikTok in a Truth Social post Friday as he tries to halt the law from taking effect.

If the Supreme Court decides not to intervene, TikTok will be unavailable everywhere in the U.S., including in Wisconsin, starting Jan. 19.

Congress says the popular video app poses a looming threat to the nation’s security because of its Chinese owner. What the justices decide could determine if the app is shut down.

The law that could ban TikTok is coming before the Supreme Court. The justices largely hold the app’s fate in their hands as they hear the case Friday.

The U.S. Supreme Court on Friday will hold a hearing on the ban of TikTok, which carries implications on the global marketplace, technology, freedom of speech and national security.

Justices will hear arguments in two consolidated cases taking aim at the federal law, which requires Chinese-owned ByteDance to divest from TikTok, or else TikTok will be banned from U.S. app stores and from being hosted by American internet service providers.

The Supreme Court seemed likely to uphold a new law that could force TikTok to shut down in the U.S., with conservative and liberal justices alike expressing skepticism about the legal challenge.

The high court’s action clears the way for the president-elect to be sentenced for his criminal conviction in Manhattan on Friday.

President-elect Trump was sentenced Friday in his hush money conviction, but the judge overseeing the case opted to not impose any punishment in a brief hearing in New York in which Trump and his attorney appeared virtually.