Donald Trump's personal Twitter account is the subject of a lawsuit filed on Tuesday by several users of the platform, including seven people whose accounts were blocked by the president after expressing their views in response to his posts.

The lawsuit argues (pdf) that by blocking users from viewing and replying to the account's tweets, Mr. Trump and members of his communications team are violating the users' First Amendment rights.

The group is represented by the Knight First Amendment Institute at Columbia University. Most of the plaintiffs, who include a sociology professor, a police officer and former Guantanamo Bay guard, and several writers, questioned or criticized Donald Trump and his policies by tweeting at his account before they were blocked. One, a writer named Joe Papp, was blocked a day after he responded to Trump's withdrawal from the Paris Agreement on climate change and the president's statement that he "was elected to represent Pittsburgh, not Paris."

Why didn't you attend your #PittsburghNotParis rally in DC, Sir? #fakeleader

— Joe Papp (@joepabike) June 3, 2017

The Knight First Amendment Institute also joined the suit, arguing that even though it has not been blocked by @realDonaldTrump, the blocking of other users is a violation of its First Amendment right to hear from others in what should be considered a public forum.

The Twitter account in question is the same one that Trump used before he became president, but the suit argues that because Trump's heavy Twitter use has changed the way an American president engages with the public, his account deserves special distinctions. It states:

Because of the way the President and his aides use the @realDonaldTrump Twitter account, the account is a public forum under the First Amendment...Defendants have promoted the President's Twitter account as a key channel for official communication...The President's advisors have stated that tweets from @realDonaldTrump are 'official statements', and they have been treated as such by politicians, world leaders, the National Archive and Records Administration, and federal courts.

The Institute sent a letter to the White House in June asking Trump and his staff to unblock the users; the suit was filed after the letter was ignored.

Some aren't convinced that Trump's Twitter account qualifies as a public space. Following news of the Institute's letter to the White House, Bloomberg columnist Noah Feldman argued that free speech rights don't exist on Twitter because the platform is a private company.

"Trump's account is a stream of communication that’s wholly owned by Twitter, a private company with First Amendment rights of its own," wrote Feldman. "Twitter can establish any rules it wants in its private domain. That includes allowing users to block anyone they choose, for any reason."

But the lawsuit argues that Twitter has been characterized as a public space recently by the Supreme Court. In Packingham vs. North Carolina in June, the Court ruled (pdf) that barring registered sex offenders from using social media sites including Twitter was unconstitutional. It characterized Twitter as part of "the modern public square" and noted, "users can petition their elected representatives and otherwise engage with them in a direct manner. Indeed, Governors in all 50 States and almost every Member of Congress have set up accounts for this purpose."