Article continues below advertisementKing Charles III is preparing for a headline-making return to Washington that promises royal spectacle, political symbolism, and no shortage of underlying tension.The British monarch, joined by Queen Camilla, will travel to the United States later this month for a state visit that coincides with the 250th anniversary of American independence. But beyond the ceremonial pomp, the trip is unfolding against a complicated geopolitical backdrop that could shape its tone.