AMNA NAWAZ: TikTok has closed a deal to keep the wildly popular video sharing app used by more than a billion people worldwide available in the U.S.

The agreement caps a six-year legal and geopolitical fight after Congress passed a law requiring TikTok to divest from its Chinese parent company or face a nationwide ban.

GEOFF BENNETT: The Trump administration says the deal protects American users from potential Chinese influence.

But, as Nick Schifrin reports, many national security experts argue it falls short.

NICK SCHIFRIN: Today on TikTok, a presidential victory dance on the beloved video sharing app that the Trump administration has now saved for 200 million Americans.

WOMAN: You know you're getting a legit Labubu, Is not a Lafufu.

NICK SCHIFRIN: TikTok's viral sensations have combined access to music with editing tricks made easy to create a social media monster.

DONALD TRUMP, President of the United States: I have a warm spot in my heart for TikTok.

NICK SCHIFRIN: And from one social media platform to another, President Trump announced the deal on TRUTH Social, that TikTok U.S.

would be owned by -- quote -- "a group of great American patriots and investors."

A TikTok press release says that tech giant Oracle will house Americans' data and secure the TikTok U.S.

app, which will not have to be redownloaded.

TikTok U.S.

will -- quote -- "retrain, test and update the algorithm," although it will still be owned by Chinese parent company ByteDance.

TikTok U.S.

board of directors will be majority American.

And the largest investors are Oracle, the Emirati firm MGX, and the American firm Silver Lake, each of which owns 15 percent.

ByteDance retains 19.9 percent.

But the app's critics argue TikTok is built with an internal sleight of hand.

WOMAN: How are you doing that?

MAN: I got a Nimbus 2000.

NICK SCHIFRIN: And that the app allows Beijing to manipulate content and steal Americans' data, even after today's announcement.

MICHAEL SOBOLIK, Senior Fellow, Hudson Institute: It's unilateral surrender to Beijing.

NICK SCHIFRIN: Michael Sobolik is a senior fellow at the Washington, D.C., think tank the Hudson Institute.

The announcement says that the new U.S.

TikTok will -- quote -- "retrain, test and update the algorithm."

What's wrong with that?

MICHAEL SOBOLIK: The real concern here isn't the data that it's being trained on.

It's what the algorithm is emphasizing or censoring.

And Beijing is going to be the one that retains control over those decisions.

And that is not only a doomsday scenario in the future.

There's a track record of TikTok doing this in recent years.

In 2023, pro-Hamas content was boosted significantly on the app right after the October 7 attacks in Israel by Hamas.

We are allowing ByteDance, it appears, to retain control over this all-important algorithm.

That signals a lack of resolve and weakness on the administration's part that they're not taking national security as seriously as they should.

The president got bad advice on this deal.

I know he loves a good deal, but this is the art of the steal, not the art of the deal.

NICK SCHIFRIN: This deal says that U.S.

users' data will be protected by Oracle.

Oracle has run the cloud for the CIA, for the intelligence community for many years.

So what's wrong with that?

MICHAEL SOBOLIK: Remember that Oracle has already been serving TikTok in this way for the past few years.

There's been numerous investigations from Forbes, from BuzzFeed, and other outlets that have demonstrated that ByteDance, again, a Chinese company, has gone to TikTok and requested us user information data outside of normal channels.

That is deeply concerning, and that happened under Oracle's watch.

NICK SCHIFRIN: But I spoke to some other technology experts today who wouldn't give me an interview on camera, but argued this deal does protect Americans.

They say that there will now be multiple layers of oversight for American users' data, for the algorithm and the TikTok app.

And they argue this deal includes the U.S.

government's most rigorous cybersecurity and data protection standards, which apply to no other social media company.

DONALD TRUMP: It's a great honor to be with a friend of mine really for a long time now.

NICK SCHIFRIN: But critics of the president's China policy who want him to confront Beijing see TikTok as a symbol of the president's prioritizing deals over national security.

MICHAEL SOBOLIK: It says that our national security is for sale at the right price, which is a dangerous message to send to the ruler of the Chinese Communist Party.

NICK SCHIFRIN: U.S.

officials dispute that... DONALD TRUMP: To all of those young people of TikTok, I saved TikTok, so you owe me big.

NICK SCHIFRIN: ... and say national security concerns and the demands of hundreds of millions of users have now been answered.

For the "PBS News Hour," I'm Nick Schifrin.