If Britain wants to remain a reliable partner in our security alliance, it must be willing to defend its sovereignty. As much as President Trump uses unpredictability as a diplomatic tool, I can predict one thing for sure: there is no way he will allow Britain to give up its sovereignty over the Chagos Islands.

Just three months into power, Labour pulled off what it billed as a diplomatic coup: ending a long-running dispute over the status of the Chagos Islands, one of Britain’s final imperial possessions, while protecting a joint U.K.-U.S. military base there for decades to come.