HARRISBURG, Pa. (AP) — The owners of twelve Pennsylvania casinos are asking the state’s highest court to declare that a tax on slot machine revenue is unconstitutional because the state doesn’t impose it broadly on cash-paying electronic game terminals known as skill games that can be found in many bars and stores. The lawsuit, filed Monday, could endanger a tax that delivers more than $1 billion annually to the state and local governments for property tax rebates and economic development projects. The lawsuit asks the court to force the state to either apply the same tax rate to skill games or to bar it from collecting taxes on slot machines.