A federal judge in New York ruled Wednesday that President Donald Trump is not allowed to block people from looking at his Twitter Inc. account because of views they have expressed.

In a 75-page ruling, New York District Court Judge Naomi Buchwald handed a victory to the seven users and Knight First Amendment Institute at Columbia University that sued Trump and other administration officials. Buchwald said Trump and administration officials cannot block Twitter users because it would violate the First Amendment. But, Trump should still be able to mute them, the judge wrote. Muting users would prevent Trump from viewing their tweets but would still allow them to view the president’s feed.

Twitter TWTR, +6.08% declined to comment.

Administration lawyers will almost certainly appeal the decision and its unlikely Trump will change practices until an appeal is decided, professor of law at U.C. Hastings Rory Little told MarketWatch in a telephone interview. “It’s an interesting First Amendment question because Twitter is too new and we’ve never had a president that’s tweeted like this before.”

“The judge didn’t order the president to do anything here,” Little said. “It’s a very mature, respected judge here and it was a cautious ruling. It says that she expects the president to follow this ruling because the president will follow all constitutional rulings.”

Lawyers from the First Amendment Institute argued that the @realDonaldTrump account is a public forum and that as a result, the president can’t block users because they are critical of him in their replies. Government lawyers have argued the opposite: that Twitter isn’t a public forum and that people have not been excluded from it in a meaningful way.

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Buchwald wrote in her decision that Trump and White House Director of Social Media Dan Scavino operate the @realDonaldTrump as an official account. “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,” she wrote in the decision.

The key concept the ruling discusses is the doctrine of public forums, which the Supreme Court has said allows people to voice opinions and not be blocked from doing so based on those opinions. But Twitter is different, both because it is so new and because the technology offers options that haven’t existed in the past: the mute button.

That Buchwald would still allow Trump and other officials to mute people are truly uncharted waters. “That’s an interesting distinction in a public forum case that hasn’t happened before,” he said.

Trump administration lawyers and the plaintiffs in the case said at a previous hearing that they were both receptive to the idea of Trump muting accounts rather than blocking them, according to a report from Reuters.

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Twitter stock was up 0.6% to $33.07 in midafternoon trading Wednesday. Twitter shares are up 37% this year after the company has reported two consecutive quarters of profitability — the first two in the company’s history as a public company.