California Governor Gavin Newsom and California Attorney General Rob announced that they have filed a lawsuit in federal court, challenging the tariffs imposed by the Trump Administration on 16 April 2025.

In the lawsuit, Governor Newsom and Attorney General Bonta argued that President Trump’s use of emergency powers to enact broad-sweeping tariffs hurt states, consumers, and businesses.

The lawsuit contends that President Trump lacks the authority to unilaterally impose tariffs under the International Emergency Economic Powers Act, creating immediate and irreparable harm to California, the nation’s largest economy, manufacturing, and agricultural state.

These tariffs have disrupted supply chains, inflated costs for the state and Californians, and inflicted billions in damages on California’s economy, the fifth largest in the world.

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

“The President’s chaotic and haphazard implementation of tariffs is not only deeply troubling, it’s illegal. As the fifth largest economy in the world, California understands global trade policy is not just a game. Californians are bracing for fallout from the impact of the President’s choices — from farmers in the Central Valley, to small businesses in Sacramento, and worried families at the kitchen table — this game the President is playing has very real consequences for Californians across our state. I am proud to go to bat alongside Governor Newsom to fight for California’s vibrant economy, businesses, and residents,” said Attorney General Rob Bonta. 

The lawsuit, filed in the United States District Court for the Northern District of California, requests the court to declare the tariffs imposed by President Trump void and enjoin their implementation.

The President lacks authority to enact unilateral tariffs

The lawsuit argues that President Trump lacks the authority to unilaterally impose tariffs against Mexico, China, and Canada or create an across-the-board 10% tariff. The President’s use of the International Economic Emergency Powers Act (IEEPA) to enact tariffs is unlawful and unprecedented.

The IEEPA gives the President authority to take certain actions if he declares a national emergency in response to a foreign national security, foreign policy, or economic threat. The law, which was enacted by Congress in 1977, specifies many different actions the President can take, but tariffs aren’t one of them. In fact, this is the first time a president has attempted to rely on this law to impose tariffs.

Supreme Court precedent

The lawsuit invokes the US Supreme Court’s major questions doctrine, which holds that in novel matters of vast economic and political significance, federal agencies and the executive branch must have clear and specific authorisation from Congress. In recent years, the Court has applied this standard to strike down major initiatives, including President Obama’s Clean Power Plan and President Biden’s student loan forgiveness programme, ruling that novel executive actions with broad impacts on the national economy cannot rest on vague statutory authority.

It is difficult to imagine a more economically significant set of actions than the one Trump is taking on tariffs, which have inflicted hundreds of billions of dollars in economic losses on a whim, using a statute that doesn’t mention tariffs. The Court, applying this doctrine even-handedly, will find that such expansive action absent congressional approval is a clear violation of the law.

Tariffs irreparably harm California businesses and consumers

As the largest economy in the nation, the largest agricultural state in the nation, and the largest US trading partner, the harm of the tariffs on the state of California is immense. President Trump’s policies have already inflicted hundreds of billions of dollars in economic losses.

Tariffs have an outsized impact on California businesses, including its more than 60,000 small business exporters.

Standing up for California families and businesses

Governor Newsom has responded quickly to help reduce negative impacts from the Trump tariffs on California’s economy and maintain California’s strong partnerships worldwide. The lawsuit follows the Governor’s recent announcement of California’s goal to create new strategic trade relationships with international partners aimed at strengthening shared economic resilience and protecting California’s manufacturers, workers, farmers, businesses, and supply chains. The Governor has also announced a new international campaign to help maintain the strong tourism partnership between California and Canada.

Earlier, on 30 January 2025, President Trump signed an executive order imposing a 25% border tax or tariff on imports from Canada and Mexico. The Trump administration also plans to impose tariffs of up to 245% on imports from China, which was initially set at 10%.

On 2 April 2025, Trump signed an executive order implementing a 10% tariff on imports from all countries, including China. The tariffs targeted nations with the largest US trade deficits. However, on 9 April 2025, he announced a three-month suspension of these tariffs, except for China.