The fate of the social media platform TikTok, which boasts something like a billion and a half users worldwide and more than 150 million in America, is emerging as one of the central dramas in the earliest days of the second Trump administration. On Sunday, he posted “SAVE TIKTOK!” to his Truth Social account.

The prospect that President Trump is set to throw the platform a lifeline is alarming even his allies in Congress and could suggest that national security concerns related to Communist China are being weighed against political and financial concerns. At a press conference at Mar-a-Lago in December, the then president-elect shared that he has “a warm spot in my heart for TikTok.”

What does that mean? The survival of the platform in America, after all, was thrown into doubt after the Supreme Court on Friday, in a unanimous decision, upheld as constitutional the Protecting Americans from Foreign Adversary Controlled Applications Act. That law bans American  companies from providing services to TikTok unless American operation of the platform is severed from Chinese control.

The Nine report that in 2023 American users uploaded five and a half billion videos onto TikTok, which were viewed more than 13 trillion times. The law was meant to go into effect yesterday, after a 270-day incubation period. There is a provision, though, that the president can grant a 90 day extension — but only if progress is made toward divesting TikTok from Beijing’s grip.

That deadline has now passed. It is, moreover, to Congress, not the president, that the Constitution grants the power to regulate “Commerce … with Foreign Nations.” That suggests that in a legal battle an executive order could be unavailing. President Biden signed the law into effect, but its future is now Mr. Trump’s and Congress’s to determine.

The 47th president took to Truth Social on Sunday to declare that  “I’m asking companies not to let TikTok stay dark!” He also vowed to “issue an executive order on Monday to extend the period of time before the law’s prohibitions take effect, so that we can make a deal to protect our national security.”

TikTok’s chief executive officer, Shou Chew, was in attendance at the inauguration and posted his own video to the platform declaring that “I want to thank President Trump for his commitment to work with us to find a solution that keeps TikTok available …We are grateful and pleased to have the support of a president who truly understands our platform.”

The unanimous court, though, recognized as valid America’s   “interest in preventing a foreign adversary”  — Communist China  — “from collecting vast swaths of sensitive data about the 170 million U. S. persons who use TikTok.” The justices also reckoned that  “TikTok’s very operation in the United States implicates the Government’s data collection concerns.”

During oral arguments in the TikTok case — captioned TikTok v. Garland — Justice Sonia Sotomayor worried that a president could intervene in just such a way as Mr. Trump has vowed to do. She expressed her concern that “a president elect or anyone else should not enforce the law when the law is in effect.” She reckoned that if the company did not shut down on the 19th, that would be a “violation of the law.” 

One senator, Kevin Cramer of North Dakota, told CNN that he is 

“not sure what the legal authority is for a president to issue an executive order down to a law that was just passed and upheld by the Supreme Court of United States.”

Two other senators, Tom Cotton and Pete Ricketts, reckoned in a statement that “there’s no legal basis for any kind of ‘extension’ … For TikTok to come back online in the future, ByteDance must agree to a sale that satisfies the law’s qualified-divestiture requirements.”

Messrs. Ricketts and Cotton warn of the “grave threat” TikTok poses to this country, but the company is celebrating Mr. Trump’s apparent openness to act to protect it. The company took to X to “thank President Trump for providing the necessary clarity and assurance to our service providers that they will face no penalties for providing TikTok to over 170 million Americans.”

Lawmakers have for years warned that TikTok is something of a Trojan Horse for the powers who sit at Beijing. Senator Hawley explained on Friday that “if you have TikTok on your phone currently, it can track your whereabouts, it can read your text messages, it can track your keystrokes. It has access to your phone records.”

The platform in 2022 claimed to take measures to protect data security, but Washington has deemed those insufficient. TikTok briefly went dark on Saturday night, but was back around 12 hours later with a notification for users that read “Thanks for your patience and support. As a result of President Trump’s efforts, TikTok is back in the U.S.!”