A person stands in front of a rustic building with the California flag in the background.
California Gov. Gavin Newsom stands in front of a state flag during a news conference in Ceres in April 2025. (File photo by Noah Berger/Associated Press)

California Gov. Gavin Newsom on Wednesday sued the Trump administration, challenging the president’s authority to impose sweeping tariffs that have set off a global trade war.

The lawsuit argues that President Donald 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 but doesn’t allow the president to adopt tariffs, the suit says.

The lawsuit, which was filed in the U.S. District Court for the Northern District of California, also argues that enacting such tariffs requires approval from Congress.

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.

A White House official slammed the lawsuit and defended the tariffs plan.

“Instead of focusing on California’s rampant crime, homelessness, and unaffordability, Gavin Newsom is spending his time trying to block President Trump’s historic efforts to finally address the national emergency of our country’s persistent goods trade deficits,” White House spokesperson Kush Desai said. “The entire Trump administration remains committed to addressing this national emergency that’s decimating America’s industries and leaving our workers behind with every tool at our disposal, from tariffs to negotiations.”

Newsom, a Democrat, said the tariffs have essentially resulted in inflated costs and could bring billions of dollars in damage to California, which has the largest economy and is the largest importer among U.S. states. Many businesses have told state officials they will start passing the cost of tariffs to consumers. The state budget could take a major hit with the tumbling stock market because California disproportionately relies on income tax revenues from capital gains — mostly money made from investments and stocks — from its wealthiest taxpayers. The additional costs from tariffs could also hamstring the state’s ability to plan for the future and pay for services, the suit states.

“No state is poised to lose more than the state of California,” Newsom said Wednesday at a news conference.

California has filed more than a dozen lawsuits challenging Trump’s policies this year. But the tariffs lawsuit marks the first time this year that Newsom, who is already considered a top 2028 presidential prospect, has been a plaintiff. The Democratic governor scaled back his anti-Trump rhetoric after January’s deadly Los Angeles fires as the state sought federal support.

Newsom discussed the lawsuit at an orchard in the farm-rich Central Valley, highlighting California’s status as a farming powerhouse, with many of the nuts, fruits and vegetables grown in the state destined for other countries.

Christine Gemperle, a second-generation almond farmer in the Central Valley, said her farm has survived three droughts and the COVID-19 pandemic over the decades, but she’s uncertain how the family business would make it through the ongoing trade war. Farmers in California grow roughly 76% of the world’s almonds, and they rely on the global markets for materials to build farming equipment and irrigation systems.

“Will we be able to access what we need to grow our crops, and if so, will we even be able to afford it?” Gemperle said Wednesday.

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. He also launched a tourism campaign to entice Canadian visitors to California this week.

Austin is a corps member for The Associated Press/Report for America Statehouse News Initiative. Report for America is a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues. Follow Austin on X: @sophieadanna