Trump threatens to 'close' down social media platforms

Can this even be considered a free speech issue? They aren't deleting his tweet, only displaying it alongside a fact check. Of course you can try to call into question the impartiality of the fact check but that is a long way from not deciding not to show the content.

And if he decided to "close" Twitter, it would actually be a clear case of censorship from the government and a violation of free speech.

Twitter is merely labelling a tweet as being factually incorrect, it's not hiding the content.

Well, it wouldn't be, because he _couldn't do it_. He's not a dictator, despite apparent aspirations.

Real question: As the head of the Federal executive branch, who would stop him?

Well, considering how huge that branch is, if he didn’t stop once the courts ordered him to, Congress could remove him from office, and he’d be “escorted” out of the White House by the Secret Service.

Didn't Congress already impeach the president but the Senate voted to keep him in office?

Yes. But ignoring the courts would be a different thing: incompetence. See the 25th Amendment § 4[0]:

> Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President.

> ...

Basically, if Congress decides Trump is incompetent, Pence will immediately become President. No impeachment trial will be necessary. And if Trump refuses to leave the White House at that point, he will be forcefully removed. Whether that’ll actually happen remains to be seen; Section 4 has never been invoked since its ratification.

[0]: https://en.wikipedia.org/wiki/Twenty-fifth_Amendment_to_the_...