Comparative Politics/Federal, unitary, and confederate states
There are in general three types of states: federal, unitary, and confederate states.
Unitary states
editA unitary state is where only one government has sovereign power. That central government can create other bodies to exercise its power, but the central government can also eliminate them. The typical example of a unitary state is France, which has a central government located in Paris.
Federal states
editA federal state is where sovereignty is shared between relatively sovereign state governments, and an "umbrella" government of very limited, clearly defined power. Neither state nor federal governments have the power to interfere with the other's powers. The United States of America had been an excellent example of a federal state, with a federal government located in Washington, D.C. - which was a non-state, neutral and federal territory. Some consider "The War Between the States," which eliminated the right of secession, the end of the federal era. But elements of federal government lingered until at least 1913, when the states' voice in federal government, a state-appointed senate, was lost under the 17th Amendment to the Constitution of the United States.
Confederate states
editA confederate state is where sovereignty is given mostly to the regional governments, with minimal power given to the central government. Two good examples of this form of government include the original United States government under the Articles of Confederation, as well as the Confederate States of America, which believed in states' rights. In current times the best example of confederal government is the European Union.