United States v. Michigan

On April 30, 2025, the Trump administration filed a lawsuit against the State of Michigan seeking to block the State from pursuing a climate change lawsuit against fossil fuel companies. On the same day, the United States also filed a <a href="https://climatecasechart.com/case/united-states-v-hawaii/">similar lawsuit</a> against the State of Hawaii. The complaint cited a news article reporting on Michigan’s intention to file such a lawsuit. The complaint alleged that the United States was bringing the lawsuits “to vindicate its sovereign, proprietary, and parens patriae interests.” The alleged sovereign interests included ensuring that states do not interfere with federal law such as the Clean Air Act or the federal government’s “exclusive authority over interstate and foreign commerce”; the alleged proprietary interests included the U.S.’s economic interests in revenue from fossil fuel leasing on federal lands and in costs for purchasing fossil fuels; and its parens patriae interests related to protecting “the economic well-being of its citizens and the national energy market” from the “nationwide economic and constitutional injuries” allegedly caused by state lawsuits against fossil fuel companies. The United States asserted that the claims in the lawsuit Michigan intended to file were preempted by the Clean Air Act “because they impermissibly regulate out-of-state greenhouse gas emissions and obstruct the Clean Air Act’s comprehensive federal-state framework and EPA’s regulatory discretion.” The U.S. also claimed that the claims against fossil fuel companies were preempted under the Foreign Affairs Doctrine. In addition, the U.S. asserted that the anticipated lawsuit constituted unconstitutional extraterritorial regulation, in violation of due process and concepts of state sovereignty and federalism. The complaint also asserted violations of the Interstate and Foreign Commerce Clauses. The United States requested that the court declare the State's claims unconstitutional and permanently enjoin the State “from taking actions to assert … state law claims.”