On July 11, 2017, the Knight Institute filed a lawsuit in federal court against President Trump and his aides for blocking seven people from the @realDonaldTrump Twitter account based on their criticism of his presidency and policies. 

The lawsuit maintains that the @realDonaldTrump account is a “public forum” under the First Amendment, from which the government may not exclude people based simply on their views. It also claims that the White House is violating the seven individual plaintiffs’ First Amendment right to petition their government, and that by purging critics from the @realDonaldTrump account, the White House is depriving those who remain in the public forum the opportunity to hear critical voices. 

Decided on July 9, 2019, and petition for rehearing denied on March 23, 2020. In a 3–0 decision, the U.S. Court of Appeals for the Second Circuit affirmed the district court's holding that President Trump's practice of blocking critics from his Twitter account violates the First Amendment. The court denied rehearing en banc by a vote of 7–2.

On July 31, 2020, the Knight Institute filed a second lawsuit in federal court against President Trump and his staff for continuing to block critics from the @realDonaldTrump Twitter account.

Status: On April 5, 2021, the Supreme Court vacated the judgment and instructed the United States Court of Appeals for the Second Circuit to dismiss the case as moot.

Case Information: Knight First Amendment Inst. at Columbia Univ. v. Trump, No. 1:17-cv-5205 (S.D.N.Y.), No. 18-1691 (2d Cir.), No. 20-197 (Supreme Court).