Judge Naomi Reice Buchwald said in her ruling that Trump is violating the U.S. Constitution by preventing certain Americans from viewing his tweets. The social media platform, she said, is a “designated public forum” from which Trump cannot exclude individual plaintiffs.

Buchwald’s ruling was in response to a lawsuit filed last July by the Knight First Amendment Institute at Columbia University, as well as seven other plaintiffs who said they had been blocked on Twitter by Trump.

Trump’s blocks on the social media platform prevented the plaintiffs from viewing or responding to the president’s tweets when logged into their own Twitter accounts.