CHICAGO (MCT) — A Chicago-based public interest law group that opposes same-sex marriage has filed a motion in Cook County Circuit Court asking to intervene and defend the state’s marriage law against a pair of lawsuits filed in May.

The lawsuits — filed by the gay rights group Lambda Legal and the American Civil Liberties Union of Illinois — claim the state’s ban on same-sex marriage violates the Illinois Constitution’s equal protection and due process clauses. Because the Cook State’s Attorney and the Illinois Attorney General have said they agree with the lawsuits, it was expected that outside groups would attempt to step in and defend the state’s ban on gay marriage.