Transportation Secretary Sean Duffy ordered a "compliance" review of the project, hinting that $4 billion of federal funds could be at risk.

President Donald Trump canceled nearly $1 billion in federal funding for the high-speed rail project in 2019, during his first term. The Biden administration later restored the funding and, in December 2023, allocated $3.3 billion more.

Republicans have long targeted high-speed rail, despite its popularity with a majority of Californians. U.S. Rep. Kevin Kiley, who appeared with Duffy and introduced legislation in December to defund it, blasted the railway as “the worst public infrastructure failure in U.S. history.”