I have dual U.S. and Canadian citizenship. Some years ago I was flying to Boston from Montreal. I got up to the U.S. immigration guy at the airport and he dutifully asked me my citizenship. "Dual," I replied. He grunted and asked the question again. "Both," I repeated, " I was born in Canada. My entire family is American." Not impressed, he looked up and, glaring at me, said : "What citizenship are you...today?" Oh. "American," I quickly answered. After that, he smiled and waved me on with the words : "Welcome home, son."