Definition - What does Sovereign Immunity mean?
Sovereign immunity is the concept that a sovereign government, or head of state, cannot be sued without giving its consent. This concept originated from English historical periods where the reigning monarchs were claimed to be incapable of doing any wrong. In the United States, there are now channels for suing the federal government.
Justipedia explains Sovereign Immunity
Since its inception as a nation, the United States has gone through a number of changes regarding its policy on sovereign immunity. Initially it was much more strict. However, since Congress established the U.S. Court of Claims in 1855, sovereign immunity has become less and less of a reality in American government. In 1946, the Tort Claims Act waived sovereign immunity for the most part, and allowed people to sue the federal government without its permission.