The rules of U.S. citizenship are complex, anyone who is born a U.S. citizen or considered to be one under U.S. nationality law is subject to tax unless they renounce their citizenship. You do not necessarily need to have an American passport. For example, an accidental American is an individual who was born in the foreign country to one U.S. parent, who emigrated from the U.S, or was born in the U.S. and then returned to their own country in early childhood.