California Gov. Gavin Newsom announces "Vogue World: Hollywood," a fashion event that celebrates the conversation between film and fashion scheduled for October 2025, at a news conference at Chateau Marmont in Los Angeles, Wednesday, March 26, 2025. (AP Photo/Damian Dovarganes)

SACRAMENTO, Calif. (AP) — California Gov. Gavin Newsom said Wednesday that his state will file a lawsuit challenging President Donald Trump’s authority to impose sweeping tariffs that have set off a global trade war.

The suit will argue that Trump’s use of the International Emergency Economic Powers Act to impose tariffs on Mexico, Canada and China or a 10% tariff on all imports is unlawful. The act enables a president to freeze and block transactions in response to foreign threats.

The lawsuit, which will be filed in the U.S. District Court for the Northern District of California, will also argue that enacting such tariffs requires approval from Congress, Newsom’s office said in a news release.

Trump has offered many justifications for increasing tariffs, including that they are designed to spur U.S. manufacturing and stop the flow of illicit fentanyl into the country. California’s move follows rapidly changing tariff plans by the Trump administration.

Newsom says the tariffs in effect have resulted in inflated costs and billions of dollars in damage in California, which has the largest economy among U.S. states and is a massive exporter.

“President Trump’s unlawful tariffs are wreaking chaos on California families, businesses, and our economy — driving up prices and threatening jobs,” he said in a statement. “We’re standing up for American families who can’t afford to let the chaos continue.”

Newsom will discuss the lawsuit alongside California Attorney General Rob Bonta later Wednesday in the farm-rich Central Valley. California is a farming powerhouse, with many of the nuts, fruits and vegetables the state grows destined for other countries.

The state will ask the court to immediately block the tariffs.

The announcement comes days after Newsom asked countries to exempt California exports from retaliatory tariffs. No deals have yet been announced.