A bill before US Congress which would force TikTok to either sell up or face a ban has breezed through its first two tests — but don't expect an actual ban any time soon.

The Protecting Americans from Foreign Adversary Controlled Applications Act may have cleared the committee phase and the House in record time, but TikTok has some unexpected political allies, and plenty of tricks up its sleeve still.

How likely is the bill to pass?

They've been wrong before, but betting and forecaster sites such as Manifold and Metcalculus are for now projecting a more than 70 per cent chance it will clear its next hurdle — the US Senate.

Among the factors dragging that figure down is Donald Trump, who has surprised many by attacking the proposal.

Towards the end of his time in the White House, the former president advocated for a similar "sale or ban" measure, even signing executive orders to pursue it, although it never reached the crucial point for TikTok.

Trump's reversal is a wildcard in the political contest, and may sway some Trump-aligned senators who would otherwise have supported the bill.

Even without the bipartisan support it's so far enjoyed, the bill has a reasonable chance of succeeding in a Democrat-controlled chamber, in light of Joe Biden's strong support.

We won't know for a while though — the bill is likely to lose pace in the Senate, potentially adding weeks or months to its journey toward a still uncertain outcome.

Why Trump has changed his mind about TikTok

Donald Trump's new stance is less surprising when you consider his dark mood when it comes to TikTok's domestic rivals.

After the January 6 riots in 2021, Facebook banned the former president "due to the risk of further incitement of violence", although the ban has since been overturned.

These days, Trump does most of his posting on Truth Social, his own rival platform, where he's described Facebook as "the true enemy of the people" and has claimed banning TikTok would "double" the company's profits.

For the Trump campaign, it's also about Gen Z voters.

Republican strategists reportedly see TikTok as a more favourable landscape, next to other popular social media platforms.

The Pew Research Centre ranks TikTok as a top source of news for Americans under 30, and a survey it conducted in 2023 found a third regularly scroll the app for news — more than double the number in 2020.

Even Joe Biden, a long term TikTok holdout, has started posting this year.

There are also fears that younger voters might punish any candidate who supports the bill.

Last week,TikTok sent push notifications to an unknown number of its US users, urging them to contact their political representative, via a button on the screen.

It warned the effective ban would strip "170 million Americans of their Constitutional right to free expression."

The tactic seems to have worked on one level — some federal politicians have reported being overwhelmed by the volume of calls, to the point where they needed to take the phones off the hook temporarily.

It's less clear whether those calls will change the minds of politicians though.

According to Pew Research, there is voter support for a ban across the political divide, with Republicans more likely to back the move.

Sell or be banned: What will TikTok do?

If the bill does pass in its current form, Tiktok's parent company ByteDance will have six months to either sell the app or face a nationwide ban.

So far, the company has characterised the bill as a "total ban" which suggests selling isn't their first choice.

But ByteDance may not have to choose at all.

It's expected to exhaust all possible legal avenues first, which may boil down to a Constitutional fight about free speech.

The argument has worked in their favour before. In 2023, a federal judge overturned a TikTok ban in the US state of Montana, citing First Amendment concerns.

Then, if the bill passes, and if all legal challenges fail, any resulting sale is unlikely to be straightforward.

TikTok was valued at $US75 billion ($112 billion) last year, and any party who could afford it — Meta or X, for example — would most likely have to be approved by regulators on the lookout for anti-competitive deals.

And at the end of the day, even if all those bridges are crossed, users will still be able to access the app using a Virtual Private Network, or VPN — technology that's both cheap and accessible in the US.