It was supposed to be a solemn day of tradition and unity for the British royal family. Instead, the latest public appearance from King Charles, Prince William, and Princess Catherine unfolded under a cloud that continues to hang heavy over the House of Windsor. On Monday, the senior royals gathered at Westminster Abbey in London for the annual Commonwealth Day service, a high-profile event that typically celebrates the ties between the United Kingdom and nations across the Commonwealth. But this year, the atmosphere outside the historic church was tense.