Article continues below advertisementKing Charles III's upcoming visit to the United States is being framed as a celebration of history, but it's quickly becoming a test of optics, symbolism and subtle signals that could define how the trip is received on both sides of the Atlantic.Set for April 27 to April 30, the visit will mark Charles' first official trip to the U.S. as monarch, alongside Queen Camilla. The itinerary includes a White House state banquet, a rare royal garden party in Washington, D.C.