They noted that Trump had used Twitter to announce his nomination of an Federal Bureau of Investigation director, to announce a ban on transgender individuals serving in the military, to announce the firing of his chief of staff, and about his decision to sell sophisticated military hardware to Japan and South Korea.
The President has had a bone to pick with the site, arguing that Twitter and Facebook are biased against him and fellow conservatives.
The Knight First Amendment Institute at New York's Columbia University filed a lawsuit in July 2017 against the President on behalf of seven Twitter users, alleging that he did not have the right to block individuals who posted critical comments in response to his tweets.
The President's use of his personal Twitter account is unprecedented, using the platform to break news, reverse plans and single out political foes.
President Donald Trump says he is planning another Fourth of July celebration in 2020 following the "tremendous success" of last week's event. By blocking users from this account, the opinion said, "the government had engaged in viewpoint discrimination".
Jameel Jaffer, the institute's director, said in an email that public officials' social media accounts are now among the most significant forums for discussion of government policy.
As for Trump, it's unknown if the Justice Department will challenge this ruling and pave the way for the Supreme Court to potentially rule on the case.
Two prominent public officials who are likely to be impacted by this ruling are Congresswoman Alexandria Ocasio-Cortez and Congresswoman Ilhan Omar with multiple Twitter users claiming that they have been blocked by these public officials. But the president has blocked protesters from posting replies.
Trump is not the only politician sued over blocking social media critics.
That's very true - but it doesn't necessarily follow that I'm forced to listen to it, either, nor are public officials. But the ACLU countered, "King wrapped the page in the trappings of his office and used it as a tool of governance".
"We own planes, we have the pilots, the airport is right next door (Andrews), all we need it the fuel", he said on Twitter. She and a host of other users of the social-media platform sued the U.S. president, arguing that Trump's tweets constituted a public forum.
A spokeswoman for the United States Department of Justice said officials were "disappointed" with Tuesday's decision.
Representatives for Trump argued that, among other things, the President's account was run in a personal capacity - allowing him to block people who annoy or disagree with him.