The marriage of Meghan Markle and Prince Harry is anything but ordinary. Even among royal marriages it’s unique because Meghan is American – and, like many Americans, she is biracial. But while her race isn’t a issue, her nationality is – thanks to the U.S. tax code.Prince Harry, Meet the IRS American citizens like Markle, who was born in Los Angeles, must report their worldwide income to the IRS even while living abroad. (For more, see How to Pay Taxes If You're Overseas.) She will have to file U.S. tax returns and Foreign Bank Accounting Report (FBAR) forms, assuming she...