In a surprising twist, President Donald Trump has taken a firm stance against the United Kingdom’s intention to hand over control of the Chagos Islands to Mauritius. He cautioned that this move could endanger the United States’ strategic access to its military base on Diego Garcia.

This change of heart underscores what a defense analyst has dubbed a “new Trump Doctrine.” The president’s disapproval of the Chagos deal has been compared to his controversial interest in acquiring Greenland, with concerns that Mauritius might later pull out of the agreement.

On his Truth Social platform, Trump described the UK’s decision regarding the Chagos Islands as “an act of great stupidity.”

“Astonishingly, our ‘brilliant’ NATO ally, the United Kingdom, is planning to hand over Diego Garcia, where a crucial U.S. Military Base is located, to Mauritius, and they are doing it FOR NO REASON WHATSOEVER,” Trump expressed. “It’s clear that China and Russia have taken note of this display of utter weakness.”

Trump’s stance against the transfer of Diego Garcia echoes his earlier efforts to negotiate the purchase of Greenland from Denmark.

“Trump has reversed his position, partly due to the UK’s backing of Denmark’s sovereign claims over Greenland and partly because of a newly outlined strategy by the White House,” explained John Hemmings, director of the National Security Center at the Henry Jackson Society, in a statement to Fox News Digital.

“These moves are linked and part of a ‘new Trump Doctrine’” outlined in November’s National Security Strategy,” he explained.

“Diego Garcia is a potential threat to Beijing’s strategy to control vital shipping lanes between the oil-rich Middle East and China’s industrial heartland,” he added, describing how “nearly 23.7 million barrels of oil transit the Indian Ocean every day, with the base being vital in any U.S.-China conflict over Taiwan.”

President Donald Trump addresses the audience during the annual meeting of the World Economic Forum in Davos, Switzerland, Wednesday, Jan. 21, 2026. (Evan Vucci/AP Photo)

In a separate post, Trump explicitly linked the Chagos dispute to his Greenland push.

“The U.K. giving away extremely important land is an act of GREAT STUPIDITY, and is another in a very long line of national security reasons why Greenland has to be acquired,” Trump wrote.

The Chagos Islands were separated from Mauritius during Britain’s decolonization process, a move the International Court of Justice ruled unlawful in 2019. 

The U.K. later agreed to transfer sovereignty while leasing Diego Garcia back for at least 99 years at a cost of at least $160 million annually.

Diego Garcia is a hub for long-range bombers, logistics and power projection across the Middle East, the Indo-Pacific and Africa. Around 2,500 personnel, mostly American, are stationed there.

Diego Garcia, the largest island in the Chagos archipelago and site of a major United States military base in the middle of the Indian Ocean, was leased from the U.K. in 1966. (Reuters)

“If Mauritius were to offer the islands to China after taking de jure control, it would put immense pressure on the U.S. in the eyes of international public opinion,” Hemmings explained.

“After all, once Mauritius has de jure sovereignty, it can renegotiate the lease terms or even renege on the treaty at any time it wants.

“It might also provide access to the exclusive economic zone, with all of its rich fishing grounds, to Chinese fishing fleets, adding another layer of risk to U.S. Air Force operations around the island,” Hemmings said.

“At this moment, the U.S. base at Diego Garcia is thought to be secure, with Mauritius promising the U.K. (and by proxy, the U.S.) a 99-year lease, which will not, it is supposed, interfere with the operations of the air base at all. But the devil is in the details.”

Fox News Digital has reached out to the White House for comment.