A natural-born citizen is someone who is automatically a citizen at birth by virtue of nature, rather than by statute or through the process of naturalization. The U.S. Constitution requires that the U.S. president be a natural-born citizen. Donald Trump has threatened to sue Ted Cruz over this issue, and others have already done so.[1]There are about 20 million naturalized citizens in the United States who are not “natural-born citizens.” Naturalized citizens are subject to denaturalization and deportation, which natural-born citizens are not.