Trump Must Act Quickly to Protect Diego Garcia

The Iran war once again proved the base’s importance. To ensure that the U.S. military keeps access for decades to come, Trump must endorse the Mauritius-U.K. Chagos agreement.

A U.S. Air Force B-1B Lancer bomber takes off on a strike mission in Afghanistan on Oct. 7, 2001, during Operation Enduring Freedom.

President Donald  Trump is right that the U.S. military base on Diego Garcia needs saving. But he has been misled about the threat and the best available solution. Even worse, Trump might be running out of time to secure a favorable deal over the base’s future. There are only a few weeks left for his administration to safeguard U.S. interests for decades to come.

Diego Garcia appears in the news headlines like clockwork whenever there is an American war in the Middle East. Usually this is because of the island’s role in supporting long-range bombing missions – whether in Iraq, Afghanistan, or Iran. Amid the present Israeli-U.S. war against Tehran, however, Diego Garcia has made headlines for two new reasons.

The first is that Diego Garcia came under direct fire from Iran. At least, media reports suggest that two ballistic missiles were fired at the island, which is around 3,300 miles from the Strait of Hormuz. One missile is said to have “failed in flight” while the other was likely intercepted by the U.S. military. Tehran denied the attack.

If the story is true, it would be the only time in modern history that Diego Garcia has come under direct enemy fire. The island’s unparalleled seclusion in the central Indian Ocean – thousands of miles away from continental Africa, Asia, and Australasia – is typically regarded as making it impregnable, a primary reason why the Pentagon values Diego Garcia so highly.

The second reason Diego Garcia has received media attention is that Trump has used the occasion of the Iran War to criticize Britain over plans to return sovereignty of Diego Garcia and the rest of the Chagos Archipelago (of which Diego Garcia is the largest island) to Mauritius. This is a U-turn for Trump, whose administration has (twice) indicated its support for Mauritian sovereignty over the Chagos group.

Trump is wrong to use the Chagos agreement as a political football. Even if some American audiences find the details hard to understand, insiders know that Britain’s deal with Mauritius was written with U.S. national interests top of mind. To ensure that the U.S. military has long-term and reliable access to Diego Garcia for decades to come, Trump must reverse course again and issue a third missive that endorses the British-Mauritian Chagos agreement.

Diego Garcia is governed as a British territory – part of the unimaginatively titled British Indian Ocean Territory, or BIOT. Along with the rest of the Chagos group, Diego Garcia was “held back” by London when the Colony of Mauritius received its independence in 1968. This was done so that the U.S. military could develop the island of Diego Garcia as a military base, which it did beginning in the 1970s. Today, the island is a hugely important logistics hub for U.S. naval and airpower operations in the Indian Ocean littoral.

In 2019, however, the International Court of Justice (ICJ) issued an advisory opinion that found Britain’s presence in the Chagos Archipelago to be unlawful. In the court’s view, the Chagos group had belonged to Mauritius ever since that country became independent. Britain’s occupation of the Chagos Islands was thus a clear-cut case of one country violating the sovereign territory of another.

Some in Britain dismissed (and continue to dismiss) the ICJ’s opinion as merely advisory and thus irrelevant. But British and American officials understood the grave implications of housing a vital military base within an unlawful jurisdiction. They knew that a legal fix was necessary, and looked to Mauritius – a friendly power, which made no secret of its support for the base on Diego Garcia – for an amicable solution.

In 2022, the short-lived Conservative government of Liz Truss announced plans to begin negotiations with Mauritius concerning sovereignty over the Chagos Islands. Two years later, these talks concluded with a creative solution: Britain would recognize Mauritius as sovereign over the entire Chagos Archipelago but, in exchange, Mauritius would allow Britain to act “as if” it were sovereign over Diego Garcia for a period of 99 years. The text of a treaty giving effect to these terms was published in May 2025, clarifying that Britain would pay rent to Mauritius as part of the overall deal.

The Biden administration gave its unqualified backing to the agreement – unsurprising given that the terms of the deal had been written such that nothing would change for the United States. When Trump was elected in November 2024, some opponents of the deal wondered aloud whether the new administration would move to block its implementation. But on the contrary, Trump signaled support for the agreement. This took some observers aback, but it should not have been surprising. If Britain was willing to pay the rent on a U.S. military base for a period of 99 years, what reason did Trump have to object?

With Trump’s blessing, the treaty between Britain and Mauritius meandered its way through each country’s respective approval process. In Britain, this meant enacting legislation – the Diego Garcia Military Base and British Indian Ocean Territory Bill – to give effect to the deal’s terms.

Since late January, all that has remained is for the House of Commons and the House of Lords to agree on a final text. Usually, this is a formality, and in January the Conservative leadership in the Lords indicated that they would not stand in the way of the Bill’s passage. Once MPs and peers come to an agreement, the legislation will be sent to the king for royal assent, and the treaty can be ratified.

So far, so good. But when the war against Iran broke out last month, Trump brought the parliamentary approval process to a grinding halt by using his social media megaphone to slam British Prime Minister Keir Starmer. Trump called the Chagos agreement a “big mistake” and insisted that the territory should remain under British control. Puzzlingly, these posts came just hours after the U.S. government issued its second statement confirming support for the Chagos agreement.

This is the second time that Trump has criticized the Chagos deal. The first was amid the spat between Trump, Starmer, and other European leaders concerning Greenland. Desperate to punish Starmer for daring to oppose U.S. annexation of Greenland – and seemingly in cahoots with the British Conservative leader, Kemi Badenoch – Trump played the Chagos card to embarrass Starmer at home.

Twice, then, Trump has blasted Starmer over the Chagos issue because he thought that doing so would cause some political pain to the British prime minister. He was right on each occasion. Starmer is reluctant (and perhaps unable) to go through with the Chagos agreement without the green light from Trump, making him seem weak, indecisive, and dependent upon the U.S. president. 

But this pantomime cannot go on any longer without jeopardizing U.S. national interests. The reality is that the United States needs Britain and Mauritius to finalize their deal over the Chagos Islands so that the future of the base on Diego Garcia can be assured – and, no less importantly, so that Britain is placed on the hook for paying rent on the base. If he does not act quickly, Trump may overplay his hand and do irreparable damage to U.S. interests.

Britain’s parliamentary session ends the week of April 27, just one month away. If the Diego Garcia Military Base and British Indian Ocean Territory Bill is not enacted by then, the legislative process will have to be started all over again in the next parliamentary session. The treaty with Mauritius cannot be ratified in the meantime.

There is a real risk that a long delay will bring about the treaty’s collapse, either because Mauritius withdraws its support or Britain loses interest, especially if Starmer is replaced as prime minister following local elections scheduled for May. This would be bad news for the United States

Someone close to Trump needs to explain to him: Britain is trying to do the U.S. a massive favor by agreeing to pay billions of pounds in rent so that Washington can have secure, legal access to Diego Garcia for a century to come. Responding to this generous offer by bullying Britain is hardly the epitome of sound long-term strategy. If this deal fails as a result of Trump’s refusal to take yes for an answer, there is no guarantee that the next one will be quite so favorable to Washington.

The United States badly needs Diego Garcia to be put on firm legal footing. Returning to the status quo ante will not achieve this. The present treaty will – and at no financial cost to the United States. If he wants to take advantage of what is on offer, Trump must clarify (again) that he supports the House of Lords finalizing the agreement without delay. If he does this, the Conservative Party will likely agree to support the agreement’s ratification – just as it was poised to do in January before Trump’s first social media outburst.

The fate of Diego Garcia hangs in the balance. There is not much time to waste.

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President Donald  Trump is right that the U.S. military base on Diego Garcia needs saving. But he has been misled about the threat and the best available solution. Even worse, Trump might be running out of time to secure a favorable deal over the base’s future. There are only a few weeks left for his administration to safeguard U.S. interests for decades to come.

Diego Garcia appears in the news headlines like clockwork whenever there is an American war in the Middle East. Usually this is because of the island’s role in supporting long-range bombing missions – whether in Iraq, Afghanistan, or Iran. Amid the present Israeli-U.S. war against Tehran, however, Diego Garcia has made headlines for two new reasons.

The first is that Diego Garcia came under direct fire from Iran. At least, media reports suggest that two ballistic missiles were fired at the island, which is around 3,300 miles from the Strait of Hormuz. One missile is said to have “failed in flight” while the other was likely intercepted by the U.S. military. Tehran denied the attack.

If the story is true, it would be the only time in modern history that Diego Garcia has come under direct enemy fire. The island’s unparalleled seclusion in the central Indian Ocean – thousands of miles away from continental Africa, Asia, and Australasia – is typically regarded as making it impregnable, a primary reason why the Pentagon values Diego Garcia so highly.

The second reason Diego Garcia has received media attention is that Trump has used the occasion of the Iran War to criticize Britain over plans to return sovereignty of Diego Garcia and the rest of the Chagos Archipelago (of which Diego Garcia is the largest island) to Mauritius. This is a U-turn for Trump, whose administration has (twice) indicated its support for Mauritian sovereignty over the Chagos group.

Trump is wrong to use the Chagos agreement as a political football. Even if some American audiences find the details hard to understand, insiders know that Britain’s deal with Mauritius was written with U.S. national interests top of mind. To ensure that the U.S. military has long-term and reliable access to Diego Garcia for decades to come, Trump must reverse course again and issue a third missive that endorses the British-Mauritian Chagos agreement.

Diego Garcia is governed as a British territory – part of the unimaginatively titled British Indian Ocean Territory, or BIOT. Along with the rest of the Chagos group, Diego Garcia was “held back” by London when the Colony of Mauritius received its independence in 1968. This was done so that the U.S. military could develop the island of Diego Garcia as a military base, which it did beginning in the 1970s. Today, the island is a hugely important logistics hub for U.S. naval and airpower operations in the Indian Ocean littoral.

In 2019, however, the International Court of Justice (ICJ) issued an advisory opinion that found Britain’s presence in the Chagos Archipelago to be unlawful. In the court’s view, the Chagos group had belonged to Mauritius ever since that country became independent. Britain’s occupation of the Chagos Islands was thus a clear-cut case of one country violating the sovereign territory of another.

Some in Britain dismissed (and continue to dismiss) the ICJ’s opinion as merely advisory and thus irrelevant. But British and American officials understood the grave implications of housing a vital military base within an unlawful jurisdiction. They knew that a legal fix was necessary, and looked to Mauritius – a friendly power, which made no secret of its support for the base on Diego Garcia – for an amicable solution.

In 2022, the short-lived Conservative government of Liz Truss announced plans to begin negotiations with Mauritius concerning sovereignty over the Chagos Islands. Two years later, these talks concluded with a creative solution: Britain would recognize Mauritius as sovereign over the entire Chagos Archipelago but, in exchange, Mauritius would allow Britain to act “as if” it were sovereign over Diego Garcia for a period of 99 years. The text of a treaty giving effect to these terms was published in May 2025, clarifying that Britain would pay rent to Mauritius as part of the overall deal.

The Biden administration gave its unqualified backing to the agreement – unsurprising given that the terms of the deal had been written such that nothing would change for the United States. When Trump was elected in November 2024, some opponents of the deal wondered aloud whether the new administration would move to block its implementation. But on the contrary, Trump signaled support for the agreement. This took some observers aback, but it should not have been surprising. If Britain was willing to pay the rent on a U.S. military base for a period of 99 years, what reason did Trump have to object?

With Trump’s blessing, the treaty between Britain and Mauritius meandered its way through each country’s respective approval process. In Britain, this meant enacting legislation – the Diego Garcia Military Base and British Indian Ocean Territory Bill – to give effect to the deal’s terms.

Since late January, all that has remained is for the House of Commons and the House of Lords to agree on a final text. Usually, this is a formality, and in January the Conservative leadership in the Lords indicated that they would not stand in the way of the Bill’s passage. Once MPs and peers come to an agreement, the legislation will be sent to the king for royal assent, and the treaty can be ratified.

So far, so good. But when the war against Iran broke out last month, Trump brought the parliamentary approval process to a grinding halt by using his social media megaphone to slam British Prime Minister Keir Starmer. Trump called the Chagos agreement a “big mistake” and insisted that the territory should remain under British control. Puzzlingly, these posts came just hours after the U.S. government issued its second statement confirming support for the Chagos agreement.

This is the second time that Trump has criticized the Chagos deal. The first was amid the spat between Trump, Starmer, and other European leaders concerning Greenland. Desperate to punish Starmer for daring to oppose U.S. annexation of Greenland – and seemingly in cahoots with the British Conservative leader, Kemi Badenoch – Trump played the Chagos card to embarrass Starmer at home.

Twice, then, Trump has blasted Starmer over the Chagos issue because he thought that doing so would cause some political pain to the British prime minister. He was right on each occasion. Starmer is reluctant (and perhaps unable) to go through with the Chagos agreement without the green light from Trump, making him seem weak, indecisive, and dependent upon the U.S. president. 

But this pantomime cannot go on any longer without jeopardizing U.S. national interests. The reality is that the United States needs Britain and Mauritius to finalize their deal over the Chagos Islands so that the future of the base on Diego Garcia can be assured – and, no less importantly, so that Britain is placed on the hook for paying rent on the base. If he does not act quickly, Trump may overplay his hand and do irreparable damage to U.S. interests.

Britain’s parliamentary session ends the week of April 27, just one month away. If the Diego Garcia Military Base and British Indian Ocean Territory Bill is not enacted by then, the legislative process will have to be started all over again in the next parliamentary session. The treaty with Mauritius cannot be ratified in the meantime.

There is a real risk that a long delay will bring about the treaty’s collapse, either because Mauritius withdraws its support or Britain loses interest, especially if Starmer is replaced as prime minister following local elections scheduled for May. This would be bad news for the United States

Someone close to Trump needs to explain to him: Britain is trying to do the U.S. a massive favor by agreeing to pay billions of pounds in rent so that Washington can have secure, legal access to Diego Garcia for a century to come. Responding to this generous offer by bullying Britain is hardly the epitome of sound long-term strategy. If this deal fails as a result of Trump’s refusal to take yes for an answer, there is no guarantee that the next one will be quite so favorable to Washington.

The United States badly needs Diego Garcia to be put on firm legal footing. Returning to the status quo ante will not achieve this. The present treaty will – and at no financial cost to the United States. If he wants to take advantage of what is on offer, Trump must clarify (again) that he supports the House of Lords finalizing the agreement without delay. If he does this, the Conservative Party will likely agree to support the agreement’s ratification – just as it was poised to do in January before Trump’s first social media outburst.

The fate of Diego Garcia hangs in the balance. There is not much time to waste.

Dr. Peter Harris is an associate professor of political science at Colorado State University, a non-resident fellow with Defense Priorities, and a current research fellow with the Modern War Institute at West Point.

Chagos handover to Mauritius

Diego Garcia naval base

Trump Mauritius-U.K. deal

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