A Federal system of government is comprised of a group of states or regions that have their own governmental authority, but are subsidiary to a single central government. Powers are often divided, with the states having certain responsibilities and the central government others. The division of powers is generally set constitutionally and is not easily changed.
Generally, the federal government has overall authority to conduct foreign policy, negotiate treaties and provide for the defense of the country. State powers often include local law enforcement, education and social services.
Examples of nations with Federal systems of government are India, Germany, and the United States.