Suits against states – 1795
“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”
Unless a state waives it’s sovereign immunity or consents to be sued, a state government cannot be forced into a federal court against its will.
See: Previous Amendment (Tenth Amendment) – Next Amendment (Twelfth Amendment)