The U.S. Supreme Court will hear arguments this week in a case challenging a law that seeks to ban the popular app TikTok in the United States if it is not sold by its owner, Byte Dance, which is based in China.

TikTok’s future in the United States now sits squarely in the hands of the Supreme Court, which will hear oral arguments Friday. At its core, the case features a head-on collision between national security and the First Amendment.

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