The US Supreme Court upheld California’s new humane-pork law, rejecting an industry challenge in a ruling buttressing the power of states to impose rules that have a broad economic impact on other parts of the country.

The ruling could force pork producers to implement costly changes to keep selling in the country’s most populous state. The industry argued unsuccessfully that California is violating the Constitution by regulating commerce outside its borders.

Writing for the court, Justice Neil Gorsuch said pork producers “have failed — repeatedly — to persuade Congress to use its express Commerce Clause authority to adopt a uniform rule for pork production.”

The majority splintered in some of its reasoning. Four justices said they would have let the lawsuit proceed.

The law, approved through a 2018 ballot initiative, bans the sale of pork in California unless pregnant pigs are allowed at least 24 square feet (2.2 square meters) of space. Industry groups say the practical effect is to force out-of-state producers to make costly changes. California imports more than 99% of the pork it consumes.

The National Pork Producers Council and the American Farm Bureau Federation contended the measure violates the so-called dormant commerce clause, a legal doctrine that says the US Constitution limits the power of states to regulate commerce outside their borders without congressional authorization.

(Updates with excerpt from Gorsuch opinion in third paragraph.)