The Eleventh Amendment to the US Constitution states that no Citizen of one State or Subject of any Foreign State can sue any other State government. This was the first Amendment ratified after the Bill of Rights, and was directly in response to a Supreme Court ruling that a Citizen of South Carolina in this case could sue the State of Georgia over funds promised for goods and upon delivery the funds were never received. The States did not wish to be sued like this, and both Congress and the States moved quickly. It was ratified within two calendar years of the ruling in question, and is part of what we understand as Sovereign Immunity to this day.