In the United States, state law refers to the law of each separate U.S. state. The fifty American states are separate sovereigns, with their own state constitutions, state governments, and state courts. All states have a legislative branch which enacts state statutes, an executive branch that promulgates state regulations pursuant to statutory authorization, and a judicial branch that applies, interprets, and occasionally overturns both state statutes and regulations, as well as local ordinances. They retain plenary power to make laws covering anything not preempted by the federal Constitution, federal statutes, or international treaties ratified by the federal Senate. Normally, state supreme courts are the final interpreters of state institutions and state law, unless their interpretation