What to Know A federal judge in New York on Wednesday ruled that President Donald Trump cannot constitutionally block his critics on Twitter

The judge wrote that the president's Twitter account is a "public forum" and blocking users is a violation of the First Amendment

The Knight First Amendment Institute at Columbia University sued the president last year on behalf of seven people who had been blocked

President Donald Trump cannot block people on Twitter, a federal judge in New York ruled on Wednesday.

District Judge Naomi Reice Buchwald said the president's Twitter account is a public forum and, as such, it is unconstitutional for him and his subordinates to block critics.

"We hold that portions of the @realDonaldTrump account -- the “interactive space” where Twitter users may directly engage with the content of the President’s tweets -- are properly analyzed under the “public forum” doctrines set forth by the Supreme Court, that such space is a designated public forum, and that the blocking of the plaintiffs based on their political speech constitutes viewpoint discrimination that violates the First Amendment," Buchwald wrote.

She added, "While we must recognize, and are sensitive to, the President’s personal First Amendment rights, he cannot exercise those rights in a way that infringes the corresponding First Amendment rights of those who have criticized him.

The Justice Department did not immediately respond to a message. A government lawyer did not respond to an email request for comment.

Jameel Jaffer, the Knight Institute's executive director, said in a release that his organization was pleased.

"The president's practice of blocking critics on Twitter is pernicious and unconstitutional, and we hope this ruling will bring it to an end," he said.

BREAKING: President Trump's blocking of critics on Twitter is unconstitutional, court rules. https://t.co/8fZ6cdKbAL pic.twitter.com/47a0yNYYkb — Knight First Amendment Institute (@knightcolumbia) May 23, 2018

The lawsuit was filed after Trump blocked some individuals from @realDonaldTrump, a 9-year-old Twitter account with over 50 million followers.

Justice Department lawyers had argued that it was Trump's prerogative, no different from the president deciding in a room filled with people not to listen to some.

Buchwald ruled that the tweets were made in a public forum.

"The President presents the @realDonaldTrump account as being a presidential account as opposed to a personal account and, more importantly, uses the account to take actions that can be taken only by the President as President," the judge said.

After a hearing this year, the judge had suggested that Trump mute rather than block some of his critics. At the time, a Justice Department attorney agreed that muting would enable Trump to avoid a tweet he doesn't want to read.

Twitter users can block people, which prevents them from seeing the user's feed while logged in. Or they can mute the person, which keeps the user from seeing that person's tweets and reply messages in their feed.

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