Knight First Amendment Inst. at Columbia Univ. v. Trump

President Donald Trump's Twitter account is a designated public forum and blocking users is unconstitutional viewpoint discrimination under the 1^st Amendment.

President Trump blocked Twitter the Twitter accounts of Cohen, Figueroa, Gu, Neely, Papp, and Pappas because they expressed views he disliked.

Cohen, Figueroa, Gu, Neely, Papp, and Pappas, along with the Knight First Amendment Institute at Columbia University, sued President Trump and other White House officials claiming that President Trump actions violated the First Amendment.

The District Court found that President Trump’s use of his Twitter account to conduct official business created a designated public forum in the "interactive space" and that the exclusion from that space was unconstitutional viewpoint discrimination.  The 2^nd District Court of Appeal agreed and affirmed the district court:

“We do conclude, however, that the First Amendment does not permit a public official who utilizes a social media account for all manner of official purposes to exclude persons from an otherwise-open online dialogue because they expressed views with which the official disagrees.”

A petition for Supreme Court review was filed last year.  It is not yet known whether the Supreme court will grant review.