In the national struggle over U.S. House control, perhaps no politician has more at stake than the California governor, who has emerged as the leading Democratic adversary to President Donald Trump in what many see as a lightly masked trial run for his own future White House bid.

Gavin Newsom's press office has been mocking President Trump with tweets in his style over the past few weeks.

President Trump had this comment about California Gov. Gavin Newsom during an unrelated event at the White House on Friday: REPORTER: Can you talk about the economic impact FIFA would have, and what is your message to the mayors about the safety aspect?