On April 16, the U.S. Governor Newsom's office issued a statement on Trump's tariff measures, saying the state will file a lawsuit in an effort to stop Trump's tariff policies. California's major industries from Silicon Valley to agriculture rely heavily on global trade, so it could lose billions of dollars due to tariffs. "President Trump's illegal tariff measures are causing chaos for households, businesses and our economy in California - pushing up prices and threatening jobs," Newsom said in a statement.

The lawsuit has been Newsom's most direct legal challenge to Trump's policy agenda since Trump took office in January this year. Newsom's argument is directed at the U.S. International Economic Emergency Powers Act, which Trump imposes tariffs without Congress' approval. The Democrat believes Trump has no right to impose tariffs under the law, which is consistent with a view to similar lawsuits filed by a group of U.S. businesses on Monday.