California files amicus brief opposing Trump administration's tariff policy

California Governor Gavin Newsom has filed an amicus brief supporting a lawsuit that challenges the Trump administration’s tariff policy. The move comes as concerns grow about the effects of these tariffs on both the national and state economies.

“Trump’s illegal tariffs are stagnating our economy and hurting American families. Bragging that your unlawful policies are producing ‘BETTER THAN EXPECTED’ results while the economy slowed. That’s like an F student bragging because they got a D-. We should all expect more from the executive branch. California will continue to stand up against Trump’s unlawful actions on behalf of all Americans,” said Governor Newsom.

The tariffs, imposed under the International Emergency Economic Powers Act (IEEPA), have led to higher prices for consumers and uncertainty in business planning. Consumer spending has slowed, with recent data showing only a 1.4 percent annual growth rate in the second quarter of 2025, compared to 2.8 percent in 2024. This decline is attributed to increased costs caused by tariffs.

Retailers and businesses are preparing for further impacts as new tariffs take effect in August. Price increases due to these policies could add an average of $2,400 per household in 2025, according to analysis from Yale Budget Lab.

California has been particularly affected by these economic changes. State households could face $25 billion in extra costs and a loss of over 64,000 jobs as a result of the tariffs. From January through May 2025, California businesses paid $11.3 billion in tariff costs—the highest among all states. The Port of Los Angeles operated at only 70% capacity recently, while Southern California experienced a significant drop—about 40%—in job postings related to trade and logistics.

On April 16, Governor Newsom and Attorney General Rob Bonta filed a lawsuit claiming President Trump lacks authority to impose such tariffs without Congressional approval through IEEPA, arguing it causes immediate harm to California’s economy.

“As the country braces for continuous chaos from President Trump’s illegal tariffs, standing united to fight for American consumers and businesses is more important than ever,” said Attorney General Bonta. “Today, I urge the U.S. Court of Appeals for the D.C. Circuit to affirm the District Court’s decision that President Trump’s chaotic tariffs are unlawful — not one word in the International Emergency Economic Powers Act, the Trump Administration’s vehicle for these tariffs, authorizes tariffs. These illegal tariffs will affect everything from the cost of essential household items like food and toilet paper to the cost of housing. The tariff chaos is a man-made crisis, and California families and industries will pay the price.”

The amicus brief was filed as part of Learning Resources, Inc. v. Trump—a case contesting whether IEEPA grants authority for such trade measures—and aligns with arguments presented by California officials earlier this year.

Fox Business commentators have also pointed out that “tariffs cost; they’re a tax,” emphasizing that these costs are typically passed along to consumers.