President Trump fired back at California Gov. Gavin Newsom's European diplomacy tour on Monday, calling British leaders foolish for entertaining the governor's overtures and dismissing the entire operation as out of bounds.

In an interview with Politico, Trump took direct aim at the UK's decision to sign a clean energy memorandum with Newsom during the Munich Security Conference.

"The U.K.'s got enough trouble without getting involved with Gavin Newscum."

Trump added that it was "inappropriate for them to be dealing with him." The rebuke came after Newsom spent several days on the international stage signing agreements, criticizing the administration's foreign policy, and positioning California as a rival power center to Washington.

Newsom's Shadow Diplomacy

The California governor's European swing has been anything but subtle. At the Munich Security Conference, Newsom told an international audience that the current administration is "temporary" and will be "gone in three years." As reported by Fox News, he signed a clean energy memorandum with U.K. Energy Secretary Ed Miliband that his office claims would facilitate nearly a billion dollars in new investment.

He also signed a pact with the Lviv region of Ukraine on Saturday, pledging California company involvement in the "rebuilding and resiliency" of the war-torn nation, specifically in defense, energy, and digital technologies.

And Newsom wasn't shy about his posture toward foreign leaders who have engaged with the White House:

"I can't take this complicity of people rolling over. I mean, handing out crowns, the Nobel prizes that are being given away ... it's just pathetic."

It was a continuation of the tone Newsom set weeks earlier at the World Economic Forum in Davos, where he told reporters he "should have brought a bunch of knee pads" for world leaders.

A Governor Playing President

There is a reason governors don't conduct foreign policy. The Constitution reserves that authority for the federal government, and for good reason: the United States speaks with one voice abroad, or it speaks with none. Agreements like Newsom's are typically structured as nonbinding memoranda of understanding and do not carry the force of federal treaties. They are, in other words, diplomatic theater.

But theater with a purpose. Political strategists and analysts have flagged Newsom as a possible 2028 presidential contender, and his international itinerary reads less like a governor promoting trade than a candidate building a foreign policy résumé. Davos in January. Munich in February. Agreements with Ukraine and the United Kingdom. Attacks on the sitting president are delivered from overseas podiums.

The substance matters less than the symbolism. Newsom isn't negotiating binding commitments. He's auditioning.

The Spokesperson Says It All

Newsom's team responded to Trump's criticism with the kind of statement that tells you everything about where the governor's head is. A Newsom spokesperson told Fox News Digital:

"Donald Trump is on his knees for coal and Big Oil, selling out America's future to China. Governor Newsom will continue to lead in his absence. Foreign leaders are rejecting Trump and choosing California's vision for the future."

Read that last line again. "Choosing California's vision for the future." Not America's vision. California's. A single state's governor is openly marketing himself as the alternative to the elected president of the United States while standing on foreign soil. The spokesperson didn't even try to frame this as cooperative or complementary. It was a direct challenge to presidential authority, issued as a press release.

And the claim that "foreign leaders are rejecting Trump" is doing some heavy lifting. The UK co-signed a nonbinding memorandum with a governor. That is not a geopolitical realignment. It is a photo opportunity.

What This Is Really About

Newsom's international tour collapses into something very simple once you strip away the climate rhetoric and the Ukraine solidarity language. A term-limited governor with obvious presidential ambitions is using the global stage to build contrast with the sitting president. Every handshake, every signed memorandum, every jab about "knee pads" is content for a future campaign reel.

The State Department has historically encouraged subnational diplomacy, particularly on trade. But there is a canyon between a governor leading a trade delegation to promote his state's industries and a governor telling foreign audiences that the president is temporary and that California offers a competing vision for American leadership.

One is commerce. The other is sabotage dressed in a suit.

Newsom can sign all the memoranda he wants. They carry no binding force and depend entirely on the goodwill of a federal government he's actively antagonizing. Trump's warning to the UK wasn't just political posturing. It was a reminder of a basic reality: California doesn't have a seat at the table because California isn't a sovereign nation, no matter how badly its governor wishes otherwise.

The 2028 campaign hasn't officially started. But someone forgot to tell Gavin Newsom.