Washington — Chief Justice John Roberts on Wednesday rejected an effort by South Carolina’s parks department to block a subpoena from Google that was issued as part of a multi-state antitrust lawsuit brought against the tech giant.

The subpoena dispute stems from a federal lawsuit that several states filed against Google alleging violations of federal and state antitrust laws through its online display advertising business. As part of the discovery process, Google issued a subpoena to the South Carolina Department of Parks, Recreation and Tourism for its proprietary online advertising file.

The department refused to comply with the subpoena and sought to quash it, arguing that it is shielded by 11th Amendment immunity from suits brought in federal court. Two other South Carolina agencies complied with subpoenas from Google.

A district court denied the parks department’s effort to invalidate the subpoena, finding that the state, through its attorney general, waived immunity when it voluntarily joined the federal lawsuit against Google.

The U.S. Court of Appeals for the 4th Circuit upheld the lower court order, agreeing that the attorney general waived any immunity the Department of Parks, Recreation and Tourism has.

“When the state waived its immunity by voluntarily joining the suit against Google, it ‘nullified’ any immunity defense that any of its arms, including SCPRT, could have otherwise asserted,” the unanimous three-judge 4th Circuit panel wrote in its decision.

The parks department appealed to the Supreme Court and, in addition to asking it to review the 4th Circuit’s ruling, asked the justices to pause the order requiring it to comply with the subpoena.

Lawyers for the parks department warned that if the department is forced to respond, it has to either comply with Google’s subpoena and forfeit its right to appeal because the issue may become moot, or be held in contempt of court.

“The decision below improperly intrudes into every state’s prerogative to order its own government and disregards foundational principles of federalism,” they wrote.

Google urged the Supreme Court to reject South Carolina’s request for emergency relief, arguing that halting the parks department’s compliance with the subpoena would harm the tech company’s interests in the underlying antitrust lawsuit.

A trial in that case is set for March 2025 and one set of motions are due Nov. 18. Lawyers for Google said the subpoena it served on the Department of Parks, Recreation and Tourism requires the production of records that are “highly relevant” to its defense, including information about the agency’s use of Google’s display advertising products and its assessment of those products.

“The rule SCPRT urges this court to adopt would be a recipe for manipulation and abuse,” Google’s lawyers argued. “It would allow a state to waive its own immunity by bringing suit against a defendant, while nevertheless insulating state agencies from any obligation to comply with the discovery the defendant needs to mount a defense.”