Eleventh Amendment to the United States Constitution

Amendment XI (the Eleventh Amendment) of the United States Constitution was passed on February 7, 1795 and states:

The Judicial power of the United States shall not be construed to extend to any suit in law or equity, commenced or prosecuted against one of the United States by Citizens of another State, or by Citizens or Subjects of any Foreign State.

Interpretation

This limits the jurisdiction of the Federal judicial system to exclude any suit launched by a person against a state government.

http://www.archives.gov/exhibit_hall/charters_of_freedom/constitution/amendments_11-27#11