The US Department of Justice filed a petition for writ of certiorari on Thursday with the Supreme Court, appealing a decision by the Second Circuit Court of Appeals that bars President Trump from blocking critics on Twitter.

Shortly after his inauguration, Trump blocked several Twitter users critical of him and his administration. Together with Columbia University’s Knight First Amendment Institute, seven of the blocked users filed suit in federal court claiming that the president’s actions in blocking them from viewing his Twitter account constituted an infringement on their First Amendment rights. A three judge panel of the Second Circuit upheld the district court’s ruling last year that, by blocking users from his Twitter feed, the president was engaged in unlawful viewpoint discrimination. In its decision, the court determined that Trump’s use of his account as a way of making official statements has made the account into an official public forum subject to the First Amendment.

In its petition, the Justice Department argued that by blocking certain users, Trump was not in fact engaged in state action. Trump created his Twitter account in 2009 and will retain it after he leaves office. The petition also notes that the president’s personal account is separate from the official White House Twitter account. Blocking is a feature available to all Twitter users, so when the president, as a private individual, uses that feature to block someone from his personal account, the blocking “does not constitute state action to which the First Amendment applies.”

The Knight Institute released a statement urging the Court to reject the petition. “Public officials across the country now use social media as their main means of communicating with their constituents,” said Katie Fallow, Senior Staff Attorney at the Knight Institute. “Blocking people from these forums denies them access to important information and deprives them of the opportunity to engage with the officials who represent them.”