Open this photo in gallery:

Trump’s turnaround on the high-profile TikTok issue could redefine what a national-security threat is in this context, even though the facts of the case against TikTok have not changed since the law was passed in April. The TikTok startup page is displayed on an iPhone in Ottawa on Feb. 27, 2023.Sean Kilpatrick/The Canadian Press

Gus Carlson is a U.S.-based columnist for The Globe and Mail.

Among the many riddles coming out of last week’s U.S. presidential election is this one: When is a national-security threat not a national-security threat?

The answer: when it’s TikTok. At least that’s what some advisers to president-elect Donald Trump are saying about the moves he is expected to make to amend or overturn a law passed earlier this year forcing the online platform’s parent to sell majority control to interests not linked to China’s communist government or face a ban in the U.S.

Such a turnaround on the high-profile TikTok issue would be remarkable in many ways. The most remarkable would be that it could redefine what a national-security threat is in this context, even though the facts of the case against TikTok have not changed since the law was passed in April.

When U.S. President Joe Biden signed legislation forcing TikTok’s parent ByteDance to sell or have the platform banned, the rationale was clear: The Chinese Communist Party, under whose surveillance laws the platform has to operate, could capture private personal information of the more than 180 million monthly users in the U.S.

The company was given until Jan. 19, 2025, to find new owners or face a ban. The law allows the deadline to be extended if there is evidence that a legitimate deal is pending.

TikTok is appealing the decision, arguing the ban is unconstitutional and violates the First Amendment. Its lawyers also say the tight timeline to find new owners is unrealistic, unreasonable and unfair.

Adding a twist to the tale, the rationale behind the hard action Mr. Biden took against TikTok was supported by Mr. Trump in his first term as U.S. president. In 2020, Mr. Trump signed an executive order that would have banned TikTok in the U.S. over national-security concerns unless ByteDance sold it.

So, a reversal in Mr. Trump’s thinking on the issue – and an amendment or repeal of the law – without material changes in what TikTok does and how it does it would seem to cast doubt on how the president-elect earlier viewed the severity of the threat: Mr. Trump himself saw it as serious enough to act on in 2020.

Mr. Trump’s potential softening on the issue also seems to run counter to his get-tough-on-China agenda.

Those close to Mr. Trump say he has lots of other levers to pull. Mr. Trump’s former adviser and campaign manager, Kellyanne Conway, told the Washington Post this week that he appreciates the reach of TikTok and there are “many ways to hold China to account outside alienating 180 million U.S. users each month.”

But the real reason lies in how there may also be a bit of payback – both positive and negative – embedded in Mr. Trump’s new posture on the matter. On the positive side, his softening on a sale or ban may reflect reluctance to annoy one of his biggest campaign donors, the billionaire Jeff Yass, who is a major investor in TikTok.

On the negative side, Mr. Trump’s continuing battles with Big Tech are no secret. So, a strong and unfettered TikTok would potentially pose competitive challenges to companies run by his Silicon Valley critics such as Mark Zuckerberg. In that case, the potential value of the payback would seem to outweigh any security threat – real or imagined – posed by the platform.

The timing of all this is both ironic and delicious. The deadline for TikTok to find a new owner or face a ban is Jan. 19, the day before Mr. Trump is scheduled to be inaugurated as the 47th president of the United States. Assuming a deal to find new owners is not pending, the prospect of an extension is not likely – and maybe not necessary if Mr. Trump acts quickly to give TikTok a get-out-of-jail-free card.

Whatever happens, the riddle will remain unsolved. How can something be branded a national-security threat one day and – literally – the next day it isn’t, even though no material change has occurred to the set of facts around it? In the twilight zone where politics and business intersect, there is no definitive answer.