The case came after a number of individuals brought a case against Trump after he blocked them for posting critical messages about him.
U.S. District Court Judge Gregory F. Van Tatenhove wrote that public officials "can choose whom to listen to on those platforms without offending the First Amendment".
"While we must recognize, and are sensitive to, the president's personal First Amendment rights, he can not exercise those rights in a way that infringes the corresponding First Amendment rights of those who have criticized him", she wrote. Representing a group of seven Twitter users, they sued Trump, along with Sarah Huckabee Sanders and Hope Hicks (both of whom were dismissed as defendants), and White House Social Media Director Daniel Scavino (who was not), claiming that "The White House is transforming a public forum into an echo chamber".
Defendants in Trump's case also argued the case shouldn't have been considered before the U.S. District Court judge because of "plaintiff's lack of standing". Importantly, the ruling identifies only parts of Trump's account as a public forum subject to First Amendment protections, not the entire account nor the rest of Twitter. "It establishes that social media accounts operated by a government official-even the president of the United States-constitutes a public forum".
While the Department of Justice has said that it is contemplating its next move, it's safe to assume that the ruling will be appealed.
As such the court was asked to consider whether a public official may, consistent with the First Amendment, "block" a person from his Twitter account in response to the political views that person has expressed, and whether the analysis differs because that public official is the US President.
"The judge pointed to a number of ways in which the Twitter account has been used for governmental purposes, and that's really the question", said Michael McConnell, who teaches First Amendment law at Stanford Law School. In last year's ruling about Facebook blocking, the judge held that public officials could do a certain amount of content moderation, provided that it was done in a content-neutral manner.
Other media reports said the judge advised Mr Trump to mute critics if he doesn't want to see their activities, but they would be able to see and reply his own tweets.
And that means no more blocking critics on Twitter for political speech.
In other words: I'm not going to make Trump do this, but because I've determined that the blocks are unconstitutional, it is fully expected that Scavino will fix the problem.
The ruling, which was instituted by Columbia University in 2017, comes as debates are widening about how to bridge the gap between public officials' rights to privacy and citizens' rights to free speech and demand for accountability.
However, the Federal District Court for the Southern District of NY found that this was not the case.