In 2018, California voters approved Proposition 12, which revised the State’s existing standards for the in-state sale of eggs and created new standards for the in-state sale of pork and veal products. Regarding the new pork standards, Proposition 12 prohibited the sale of pork from breeding pigs (or their immediate offspring) that are “confined in a cruel manner.” A confinement is considered “cruel” if it prevents the pig from “lying down, standing up, fully extending [its] limbs, or turning around freely.”

Shortly after the law was enacted, the National Pork Producers Council and the American Farm Bureau Federation challenged Proposition 12 in the U.S. District Court for the Southern District of California. The District Court upheld Proposition 12 as constitutional, and the U.S. Court of Appeals for the Ninth Circuit affirmed. The Supreme Court then granted certiorari.