Rule 19.Notice of Claim of Unconstitutionality or Preemption by Federal Law
Article I. General Rules · Last amended 2006 · Last verified July 20, 2026
In one sentenceRule 19 requires a party raising a constitutional or federal preemption challenge to notify the government office responsible for defending the law, giving it a chance to step in.
(a)Notice Required. In any cause or proceeding in which the constitutionality or preemption
by federal law of a statute, ordinance, administrative regulation, or other law affecting the public interest is raised, and to which action or proceeding the State or the political subdivision, agency, or officer affected is not already a party, the litigant raising the constitutional or preemption issue shall serve an appropriate notice thereof on the Attorney General, State’s Attorney, municipal counsel or agency attorney, as the case may be.
(b)Contents and Time for Filing Notice. The notice shall identify the particular statute, ordinance, regulation, or other law, and shall briefly describe the nature of the constitutional or preemption challenge. The notice shall be served at the time of suit, answer or counterclaim, if the challenge is raised at that level, or promptly after the constitutional or preemption question arises as a result of a circuit or reviewing court ruling or judgment.
(c)Purpose of Notice. The purpose of such notice shall be to afford the State, political subdivision, agency or officer, as the case may be, the opportunity, but not the obligation, to intervene in the cause or proceeding for the purpose of defending the law or regulation challenged. The election to intervene shall be subject to applicable provisions of law governing intervention or impleading of interested parties.
Plain-English Summary
Rule 19 protects the government's right to defend its own laws. Whenever a party argues that a statute, ordinance, or regulation is unconstitutional or preempted by federal law, and the government is not already a party to the case, that party must serve notice on the Attorney General, State's Attorney, or the relevant municipal or agency attorney.
The notice has to identify the specific law and briefly describe the constitutional or preemption argument. It has to go out at the time of suit, answer, or counterclaim if the challenge starts there, or promptly once the issue arises from a court ruling.
The point of the notice is not to force the government to intervene, only to give it the option. Whether the government joins the case still depends on the ordinary rules for intervention.
Frequently Asked Questions
When do I have to give notice under Rule 19?
Whenever you raise a constitutional or federal preemption challenge to a law and the government entity that would defend it is not already a party.
Who gets served with the notice required by Rule 19?
The Attorney General, the State's Attorney, or the relevant municipal or agency attorney, depending on which law is being challenged.
Does the government have to intervene once it gets notice under Rule 19?
No. The notice gives the government the opportunity to intervene and defend the law, not an obligation to do so.
What has to be in the Rule 19 notice?
It must identify the specific statute, ordinance, or regulation and briefly describe the nature of the constitutional or preemption challenge.
Is Rule 19 notice connected to Rule 18?
Yes. Rule 18 makes proper Rule 19 notice, along with a fair opportunity to respond, a precondition to a court finding a law unconstitutional.
Amendment History
Adopted February 21, 1986, effective August 1, 1986; amended July 27, 2006, effective September 1, 2006.
Source & verification. Rule text, official Committee Comments, and
amendment history are reproduced verbatim from the Illinois Supreme Court Rules,
promulgated by the Supreme Court of Illinois. Last verified July 20, 2026.
· Official source
Also known as:notify attorney general constitutional challengefederal preemption notice illinoischallenging a statute as unconstitutionalrule 19 notice requirementwho defends a state law in court