With California's budget hanging precariously in the balance, Governor Gavin Newsom filed a lawsuit mid-April seeking to block President Donald Trump's tariff powers.

The lawsuit, which Newsom and Attorney General Rob Bonta filed in federal court, argues that Trump does not have the constitutional authority to unilaterally enact tariffs.

Trump cited the United States' large trade deficit to declare a national emergency earlier this month and impose sweeping tariffs on the rest of the world.

In early April, Trump invoked the International Emergency Economic Powers Act of 1977 to establish a universal 10% tariff on all countries importing goods to the United States, with even higher reciprocal tariffs on some nations.

Then he abruptly reversed course hours after they took effect, pausing most of the reciprocal tariffs while ratcheting up the import tax on China to 145%.

The chaos tanked the stock market, a huge risk for California's forthcoming budget, which depends disproportionately on income tax revenue from capital gains earned by the wealthiest taxpayers.

The state is also particularly vulnerable to other economic pain from the tariffs because China is California's largest trading partner, propping up manufacturing, agriculture, tourism, and major ports in Los Angeles, Long Beach, and Oakland.

Other major potential impacts for California include driving up the cost of construction materials, just as Los Angeles begins rebuilding from a series of devastating fires that flattened several neighborhoods in January.

In their lawsuit filed in the US District Court in San Francisco Newsom and Bonta asked a judge to immediately pause Trump's tariffs.

The state contends that the International Emergency Economic Powers Act specifies many remedies a president can take in response to a foreign economic threat, but tariffs are not among them.

Without this specific authorization from Congress, the lawsuit argues, Trump's actions are unlawful and unprecedented.

In the wake of Trump's tariffs announcement earlier this month, Newsom said California would pursue its own strategic partnerships on international trade.

For CalMatters, I'm Alexei Koseff.