Sovereign immunity (also known as governmental immunity) in American law was derived from the British common law doctrine that the King could do no wrong—and thus could not be sued. Sovereign immunity varies from state to state, but typically applies to state governments as well as the federal government.

For example, sovereign immunity protects the state and its various provisions of state government—including agencies, boards, hospitals, and universities—from liability and from suit—unless the immunity has been waived. Similarly, sovereign immunity protects political subdivisions—including counties, cities, and school districts—from liability and from suit—unless the immunity has been waived.

Thus, sovereign immunity encompasses two principles: (1) immunity from suit and (2) immunity from liability. Immunity from suit bars a suit against the state or other governmental entity unless the Legislature expressly gives consent. Immunity from liability protects the state or other governmental entity from judgments even if the Legislature has expressly given consent to sue.

In some states, when a governmental entity contracts, it is liable on contracts made for its benefit as if it were a private person. Consequently, when a governmental entity contracts with private citizens it waives immunity from liability. But the governmental entity does not waive immunity from suit simply by contracting with a private person. Legislative consent to sue is still necessary.

But federal and state governments (generally the U.S. Congress and state legislatures) have the ability to waive their sovereign immunity. Waivers of sovereign immunity are usually included in state and federal statutes and interpreted and applied by state and federal courts in court opinions.

A party may establish legislative consent by referencing a statute or a resolution granting express legislative permission. Legislative consent to sue the state or other governmental entity must be expressed in clear and unambiguous language.

In Illinois, sovereign immunity is a legal doctrine that prevents the state government, as well as its subdivisions such as counties, cities, and school districts, from being sued or held liable in certain circumstances. This immunity can be waived by the state legislature through explicit statutes. The Illinois Court of Claims is the venue where claims against the state are typically heard, as the state has consented to be sued in this court for specific types of claims. The Illinois State Lawsuit Immunity Act generally provides the state with immunity from lawsuits, but there are exceptions, such as contracts entered into by the state, where the state is treated similarly to a private party and can be held liable. However, even when the state enters into contracts, it does not waive its immunity from suit unless there is a legislative act that expressly allows for such a lawsuit. It is important for individuals or entities seeking to sue the state or its subdivisions to consult with an attorney to understand the specific conditions under which sovereign immunity may be waived and to ensure compliance with the procedural requirements for bringing a claim.