California Gov. Gavin Newsom announced Monday that he and his wife, Jennifer Siebel Newsom, are under federal investigation, alleging that President Trump directed the Justice Department to pursue them. In a social-media video, Newsom said the probe was initiated “because I am considering running for president.” Less than three hours later, his political-action committee sent out a fundraising appeal urging supporters to help him “stand up to Trump and fight off this political witch hunt.”
Agents from the FBI and the IRS have approached more than a dozen people in Newsom’s orbit in recent weeks, aides to the governor said. The questioning has covered topics dating back five to six years, including the governor’s family and his wife’s business interests and taxes. A person familiar with the matter told The Wall Street Journal that the probes have been running since at least 2025 and were initiated by federal law-enforcement officials in California. The Justice Department has not publicly commented on the investigation.
The announcement escalates the long-running and often contentious relationship between Newsom and Trump. Since Trump returned to the White House, Newsom has positioned himself as a leading Democratic foil to the president. Steve Bannon, formerly a senior adviser to Trump and an architect of the populist MAGA movement, said in an interview that Newsom has assumed “a Trumpian attitude” that treats “politics as a combat sport.” Bannon added: “For Democrats, that plays well.”
Newsom’s tactics have drawn praise from Democrats and some Republicans. Mike Madrid, a California-based Republican strategist and co-founder of the anti-Trump Lincoln Project, said Newsom realized “he was going to have to beat him at his own game” and that “I think he has—or at least is competitive with him.” Democratic strategist Kristian Ramos told the Journal that “for somebody like Gavin Newsom, who has the ability to take the blow and turn it around to deliver his own…it’s smart politics.”
The relationship between the two men has swung between cooperation and antagonism. After Trump was inaugurated in early 2025, Newsom showed up uninvited to greet Air Force One when the president toured Los Angeles County fire damage, and the two talked in the Oval Office for more than 90 minutes as Newsom pressed for federal fire aid.
The détente collapsed in June 2025, when the Trump administration launched militarized immigration raids in Southern California. After mass protests, Trump deployed 4,000 National Guard members and 700 active-duty Marines to Los Angeles, saying he would arrest Newsom if he were the border czar. “I would do it,” Trump said. “Gavin likes the publicity, but I think it would be a great thing.”
At a March event for his memoir “Young Man in a Hurry,” Newsom recalled that “It felt like he declared war on an American city. That’s when I recognized I had to radically change.” In response to Texas plans to redraw congressional boundaries to favor Republicans, Newsom began pushing a voter initiative to temporarily replace California’s nonpartisan districts with maps favoring Democrats. He and his staff also began trolling the president on social media, mimicking his writing style with capitalized posts and signoffs like “THANK YOU FOR YOUR ATTENTION TO THIS MATTER!” An aide said it started as a joke but evolved into an effort to “hold up the mirror to MAGA.”
A White House spokeswoman said Trump has worked “relentlessly on behalf of all Americans, even when their local leaders, like Newscum, repeatedly fail them.”
Trump has not directly commented on the investigation or Newsom’s accusation that he is behind it. However, on Thursday he posted a link on Truth Social to an article about Newsom soliciting $340 million “from special interests for allies.”
The investigation moves the Newsom-Trump relationship into uncharted territory. Madrid said that while Trump once benefited from sparring with figures like Newsom, the president “doesn’t have the same fighter energy” as his approval ratings have dropped amid growing concerns over his handling of the Iran war and the economy.