The Supreme Court on June 4 delivered an important win for the Federal Communications Commission, holding 8-1 that the agency may continue imposing data-privacy fines on telecommunications carriers through its existing enforcement framework. The ruling rejects a constitutional challenge brought by ATT and Verizon and leaves intact a key tool the FCC uses to police carrier handling of customer information.

Chief Justice John Roberts wrote the majority opinion.

The U.S. Supreme Court appeared hesitant during oral argument to embrace ATT and Verizon’s effort to upend the Federal Communications Commission’s in-house penalty process, a challenge that could have reshaped how federal agencies pursue civil enforcement.

The dispute stems from FCC allegations that the telecom companies failed to adequately protect customers’ location data, allowing sensitive information to be sold or accessed without sufficient safeguards.