In the United States, federalism is the system of government in which power is divided between a central government and the government of each state. Before the U.S. Constitution was written, each American state was essentially sovereign. The U.S. Constitution created a federal government with sufficient powers to both represent and unite the states, but did not supplant state governments. This federal arrangement, by which the central federal government exercises delegated power over some issues and the state governments exercise power over other issues, is one of the basic characteristics of the U.S. Constitution that checks governmental power. Other such characteristics are the separation of powers among the three branches of government--the legislative, executive, and judicial.