During his first term as president,Donald Trumpled the effort to ban TikTok, the hugely popular video-sharing site he said posed a threat to U.S. national security. But on the eve of his return to the White House, the president-elect is being hailed as the apps savior.After going dark for users this weekend, Trump said on his social media site that he would issue an executive order after hes sworn in for a second term on Monday delaying a TikTok ban so that we can make a deal to protect our national security. He said the order would make clear that companies will not be held liable for violating a law that aimed to force TikToks sale by its China-based parent company. Hours later, the app returned, to the relief of its legions of dedicated users.Thanks for your patience and support. As a result of President Trumps efforts, TikTok is back in the U.S.! read the announcement.Trumps legal authority to unilaterally decide not to enforce the law, which passed with overwhelming bipartisan support in April andwas upheld by the Supreme Courton Friday, is unclear. But the rapid developments over the weekend served as a reminder of how dramatically debates over technology, social media, and national security have changed since Trump was last in the White House. It also signaled how closely Trump is following those shifts after waging a successful campaign in which he made inroads with voters in part by harnessing the appeal of some social media platforms.Trump can now take credit for reviving an app with 170 million users that is especially popular with younger Americans, many of whom spend hours a day on the platform to get news, make money, and find entertainment.This is one of those things where the domestic politics has become so upside down and crazy that it turns out theres only upside for Trump now, said Bill Bishop, a China expert who has been closely following the back-and-forth. If the ban ends up being enforced, he said, Trump will say it was on outgoing President Joe Bidens watch. And if it does come back then Trump is a savior. And he will be rewarded both by users, as well as the company, which he said is now beholden to Trump and will have an incentive to make sure content on the platform is favorable to him.TikToks move comes as tech companies and CEOs have been working furiously toimprove their standing with Trump. X owner and Tesla CEO Elon Musk has enjoyed unprecedented access to the president-elect after spending more than $200 million and personally campaigning to help him get elected.Meta CEO Mark Zuckerberg met with Trump at Mar-a-Lago and reshaped his social media platforms policies to align more closely with Trumps worldview earlier this month,ending third-party fact-checking, loosening rules against hate speech, ending his companys diversity and equity policies, and naming Dana White, the president and CEO of Ultimate Fighting Championship and afamiliar figurein Trumps orbit, to its board.OpenAI CEO Sam Altman, Amazon, Meta, and Google have all pledged to donate $1 million each to Trumps inaugural fund.The companies have a lot on the line, including regulatory challenges. Although federal regulators began cracking down on Google and Facebook during Trumps first term as presidentand flourished under Bidenmost experts expect his second administration toease up on antitrust enforcementand be more receptive to business mergers.TikTok also worked to curry Trumps favor, with CEO Shou Chew meeting with him at Mar-a-Lago in December and later present in Washington over the weekend for Trumps inauguration. In avideo responding to the Supreme Court decision, Chew was careful to praise Trump and cast the apps fate as dependent on him.On behalf of everyone at TikTok and all our users across the country, I want to thank President Trump for his commitment to work with us to find a solution that keeps TikTok available in the United States, he said. We are grateful and pleased to have the support of a president who truly understands our platform.When the app went dark, it had initially posted a simple message informing users of the change, but later updated the language to include Trump.Sorry, TikTok isnt available right now, it read. A law banning TikTok has been enacted in the U.S. Unfortunately, that means you cant use TikTok for now. We are fortunate that President Trump has indicated that he will work with us on a solution to reinstate TikTok once he takes office. Please stay tuned!The federal law had required TikTok parent company ByteDance to cut ties with the platforms U.S. operations by Sunday. The Biden administration had stressed in recent days that it did not intend to enforce the ban before Trump took office. But TikTok said it would nonetheless go dark because the Biden administrationhad not provided necessary clarity and assuranceto service providersa stance outgoing Deputy National Security Adviser Jon Finer cast as disingenuous.Frankly, it doesnt feel completely on the level, he said on ABCs This Week. I think we were extremely clear that there was no need to take this action, he said.Trump said inan interview with NBC Newson Saturday that he was considering granting ByteDance a 90-day extension to sell. ByteDance has repeatedly refused to sell, but the company is being eyed by investors including Trumpsformer Treasury Secretary Steven Mnuchinand billionaire businessmanFrank McCourt.Sarah Kreps, director of Cornell Universitys Tech Policy Institute, said there was no evidence ByteDance had made any meaningful progress toward divestiture, so I dont see how, by any measure, it would legally meet those conditions.Further, an Executive Order cannot legally override or cancel a law that Congress passed, she said. Laws enacted through the legislative process have a higher legal standing and an EO that conflicts with the existing law, the law takes precedence and the EO would likely be struck down by the courts.Sen. Tom Cotton, the Republican chairman of the Senate Select Committee on Intelligence, warned Sunday that there is no legal basis for the kind of extension Trump is pursuing.Any company that hosts, distributes, services, or otherwise facilitates communist-controlled TikTok could face hundreds of billions of dollars of ruinous liability under the law, not just from DOJ, but also under securities law, shareholder lawsuits, and state AGs,he wrote on X. Think about it.Trump, in his Sunday post, proposed new terms of a deal in which he said the United States would have a 50% ownership position in a joint venture that would be set up between the U.S. and whichever purchase we so choose. But the details remained murky and it was unclear whether Trump was proposing control by the U.S. government or another company. Trump did not elaborate during a rally Sunday night, where he hailed the move.As of today, TikTok is back, he said. We have no choice. We have to save it.Though Trump sought to ban TikTok during his first term, he reversed that stance during his 2024 campaign, when he came to believe a ban would help the apps rival, Facebook, which he held responsible, in part, to his 2020 election loss to Biden.Trump ended upjoining the app last yearand has grown his following to nearly 15 million users. He has since credited the app for helping him win over young voters.I have a warm spot in my heart for TikTok, he said during a December news conference. TikTok had an impact.Jill Colvin and Barbara Ortutay, Associated PressAssociated Press writers Charlotte Kramon and Nadia Lathan contributed to this report.