A divided Michigan Supreme Court has issued an opinion that would continue to prevent an energy company from discharging treated wastewater into the headwaters of the Au Sable River in Otsego County.

The 4-3 decision would deny the water discharge plan for Merit Energy Co. because the court's majority ruled it is "manifestly unreasonable."

The company already had abandoned the discharge plan and considered the case moot. A previous Supreme Court ruling would have prevented the discharge.

The new ruling, however, could set precedents for future environmental cases in which the state has issued permits.

Conservative justices who currently form the court's minority blast the more liberal majority for using a moot case to "reach desired policy results."

The court is expected to return to conservative control in 2011.