Given the strategic centrality of Diego Garcia, it is hard to imagine the US giving it up, or, rather, the British withdrawing their agreement with Washington and de-colonizing the Chagos Islands. In 2016, London extended the Americans' lease for 20 years.
Mauritius wants the Chagos back, but at this point doesn't object to the base. It certainly wants a bigger rent check and the right eventually to take the island group back. It also wants more control over what goes on at Diego Garcia. For instance, the British government admitted that the Americans were using the island to transit "extraordinary renditions," people seized during the Afghan and Iraq wars between 2002 and 2003, many of whom were tortured. Torture is a violation of international law.
As for the Chogossians, they want to go back.
Diego Garcia is immensely important for US military and intelligence operations in the region, but it is just one of some 800 American military bases on every continent except Antarctica. Those bases form a worldwide network that allows the US military to deploy advisers and Special Forces in some 177 countries across the globe. Those forces create tensions that can turn dangerous at a moment's notice.
For instance there are currently US military personal in virtually every country surrounding Russia: Norway, Poland, Hungary, Kosovo, Romania, Turkey, Latvia, Lithuania, Estonia, Georgia, Ukraine and Bulgaria. Added to that is the Mediterranean's 6th Fleet, which regularly sends warships into the Black Sea.
Much the same can be said for China. US military forces are deployed in South Korea, Japan and Australia, plus numerous islands in the Pacific. The American 7th fleet, based in Hawaii and Yokohama, is the Navy's largest.
In late March, US Navy and Coast Guard ships transited the Taiwan Straits, which, while international waters, the Chinese consider an unnecessary provocation. British ships have also sailed close to Chinese-occupied reefs and islands in the South China Sea.
The fight to de-colonize the Chagos Islands will now move to the UN General Assembly. In the end, Britain may ignore the General Assembly and the Court, but it will be hard pressed to make a credible case for doing so. How Great Britain can argue for international law in the Crimea and South China Sea, while ignoring the International Court of Justice on the Chagos, will require some fancy footwork.
In the meantime, Mauritius Prime Minister Pravard Jugnauth calls the Court decision "historic," and one that will eventually allow the 6,000 native Chagossians and their descendents "to return home"
(Note: You can view every article as one long page if you sign up as an Advocate Member, or higher).