https://www.vox.com/2019/7/9/20687778/trump-twitter-blocking-violates-constitution-2nd-circuit-appeals-court

“Once it is established that the President is a government actor with respect to his use of the Account, viewpoint discrimination violates the First Amendment.”

President Donald Trump cannot block Twitter users from following his personal account, the US Court of Appeals for the Second Circuit ruled Tuesday, affirming a lower court’s ruling that Trump has been violating the Constitution by blocking his critics.