The United States Supreme Court has overturned an earlier ruling from the Connecticut Supreme Court by deciding that the sovereign immunity of the federally-recognized Mohegan Indian Tribe does not extend to one of the employees of its Mohegan Sun enterprise.

The matter concerned William Clarke, who was working as a limousine driver on behalf of the Mohegan Tribal Gaming Authority and its Mohegan Sun casino in Connecticut when he was involved in an automobile accident in which plaintiffs Brian and Michelle Lewis were seriously injured. The non-Indian couple alleged that a vehicle in which they had been riding was struck by the defendant’s in the October of 2011 incident and that he should be required to pay compensation.

However, last year saw the Connecticut Supreme Court unanimously decide against the couple after ruling that Clarke was entitled to sovereign immunity as he had been “acting within the scope of his employment when the accident that injured the plaintiffs occurred”. In his explanation of the decision in the Lewis v Clarke court case, Connecticut Supreme Court Justice Dennis Eveleigh wrote that it was well established that “the doctrine of tribal immunity extends to individual tribal officials acting in their representative capacity and within the scope of their authority”.

But, the United States Supreme Court disagreed on Tuesday and the case is now due to be sent back to the Connecticut Superior Court in New London where it will be heard on its merits.

“The employee, not the tribe, is the real party in interest and the tribe’s sovereign immunity is not implicated,” United States Supreme Court Justice Sonia Sotomayor wrote in the body’s twelve-page majority opinion. “We are cognizant of the Connecticut Supreme Court’s concern that plaintiffs not circumvent tribal sovereign immunity but here that immunity is simply not in play. Clarke, not the [Mohegan Tribal] Gaming Authority, is the real party in interest.”

In his concurring opinion, United States Supreme Court Justice Clarence Thomas wrote that Clarke could not assert immunity because the Lewis’ suit arose from “an off-reservation commercial act” while colleague Ruth Bader Ginsburg sided with dissenting opinions in other cases that “explain why tribes, interacting with non-tribal members outside reservation boundaries, should be subject to non-discriminatory state laws of general application”.

“The Mohegan [Indian] Tribe is proud to have defended its right, one shared with the federal government, state governments and foreign governments and recognized by the state of Connecticut in a tribal-state compact, to channel suits against its own employees to its own judicial system,” read a statement from the Mohegan Indian Tribe. “Although the [United States] Supreme Court did not agree with the reasoning of the Connecticut Supreme Court, we are heartened that it left open the possibility that other legal principles may nonetheless require this suit against Clarke, a former employee of the Mohegan [Indian] Tribe, to proceed in tribal court. We will continue to work to ensure that claims against the tribe’s employees are brought in a fair, equitable and appropriate forum.”

The tribe’s Mohegan Gaming Disputes Court earlier resolved a claim brought by the couple who had been passengers in the limousine Clarke was driving at the time of the accident on Interstate 95 in Norwalk.