The Supreme Court on Friday set new ground rules for when public officials can block critical voices from their social media accounts, ruling in two of several tech-focused cases this term that will shape the future of online interactions between the government and its citizens.

In a pair of unanimous decisions, the court acknowledged the challenge of determining when public employees are acting in an official capacity on social media — and therefore must adhere to First Amendment restrictions on censorship — and when they are acting as private citizens with their own constitutional rights.

Writing for the court, Justice Amy Coney Barrett said: “The distinction between private conduct and state action turns on substance, not labels: Private parties can act with the authority of the State, and state officials have private lives and their own constitutional rights. Categorizing conduct, therefore, can require a close look.”

Public officials can be sued for blocking or deleting critical commentary, the opinion said, if a public employee has the “actual authority to speak on the state’s behalf” and “purported to exercise that authority” in the social media post at issue.

The court said government officials can go a long way in protecting themselves from liability by clearly labeling a private account as “personal.”

“A public official who fails to keep personal posts in a clearly designated personal account therefore exposes himself to greater potential liability,” Barrett wrote.

The cases before the justices involved a city manager in Michigan and two school board members in California. They presented a fresh opportunity for the high court to provide guidelines for when public officials can bar critical voices from social media accounts, which are increasingly used by governors, mayors, police chiefs and other public officials to communicate with citizens.

Separately this term, the justices will decide whether laws passed in Texas and Florida can restrict social media giants from removing certain political or controversial posts. On Monday, the court will hear oral argument on whether the Biden administration’s attempts to influence the content curation decisions of social media platforms violate the First Amendment.

The Supreme Court returned both of the cases decided Friday to their respective appeals courts for further review in light of the newly outlined ground rules.

Some legal experts said the court’s test was not as clear as it could have been and will probably be difficult for lower courts to apply because it depends heavily on the specific facts and circumstances of each case.

“This case doesn’t tell us much new about how to understand the liability of the 20 million people who work in local, state, administrative or federal government in the U.S. … just that the question is complicated,” said Kate Klonick, an online-platform regulation expert who teaches at St. John’s Law School.

Katie Fallow, senior counsel for the Knight First Amendment Institute at Columbia University, said the court’s ruling does not sufficiently address public officials’ widespread use of personal “shadow accounts,” which constituents often perceive as official.

The court was “right to hold that public officials can’t immunize themselves from First Amendment liability merely by using their personal accounts to conduct official business,” Fallow said in a statement. “We are disappointed, though, that the Court did not adopt the more practical test used by the majority of the courts of appeals, which appropriately balanced the free speech interests of public officials with those of the people who want to speak to them on their social media accounts.”

The high court in 2021 declined to take up a case in which a lower court had ruled that President Donald Trump could not block critics from his feed on Twitter, now X. After Trump lost reelection, and Twitter canceled his account, the Supreme Court vacated the appeals court decision, saying the matter was moot.

Under the court’s new test, Fallow said, Trump would not have been permitted to block critics from his personal account because he clearly had the authority to speak on behalf of the office and used the account to unveil official policy pronouncements.

In both cases decided Friday, the Biden administration backed the government officials, saying they had the right to block users from their private accounts, which they categorized as a type of private property, because they were not acting in an official capacity.

In the first case, James Freed, the city manager of Port Huron, Mich., was sued after he blocked a constituent’s critical comments in response to a Facebook post about the city’s coronavirus pandemic policies. Kevin Lindke said Freed violated the First Amendment when he deleted Lindke’s comments and blocked his account.

The U.S. Court of Appeals for the 6th Circuit sided with Freed, who described himself on his Facebook page as a father, husband and city manager, and listed the city’s website and general email as his contact information. Although Freed posted about city affairs, the overall content on the page he created before his appointment as city manager tended toward family activities, according to court filings.

In the second case, Christopher and Kimberly Garnier, a Southern California couple who regularly posted critical messages on the Facebook pages of two school board members, were blocked from those pages — and then filed a lawsuit.

The U.S. Court of Appeals for the 9th Circuit sided with the Garniers in a broad ruling that said the decision of the school board members to block the couple could be considered a government action, because of the appearance and content of the school board members’ Facebook pages.

Throughout the 18-page opinion in the case from Michigan, the high court emphasized that public officials have their own constitutional rights to maintain private accounts and can block critical voices without violating the First Amendment. But they also said public officials may not be shielded from liability in some circumstances, when they use their personal accounts to carry out official business directly tied to their official responsibilities.

State and local officials who routinely interact with the public “may look like they are always on the clock, making it tempting to characterize every encounter as part of the job,” the court said. “While public officials can act on behalf of the State, they are also private citizens with their own constitutional rights.”

The cases are Lindke v. Freed and O’Connor-Ratcliff v. Garnier.

Will Oremus contributed to this report.