Britain’s King Charles and Queen Camilla arrived in the United States on Monday afternoon for a four-day trip, welcomed by self-proclaimed royal fan Donald Trump even as the US president has differed with the British government over the Iran war. The state visit, by far the most high-profile and consequential of Charles’ reign, marks the 250th anniversary of the US declaration of independence from British rule, and is the first to the country by a British monarch for two decades. After landing...