The Constitution doesn't define "natural-born citizen;" as generations of jurists have pointed out, much of that document's brilliance lies in its ambiguity. But a little research showed that the question had actually been asked and answered way back in 1790, when the very first Congress passed a statute declaring that "the children of citizens of the United States, that may be borne beyond sea, or out of the limits of the United States, shall be considered as natural-born citizens of the United States." The Senate unanimously passed a resolution recognizing that "John Sidney McCain III is a natural-born citizen." On to more important things.
Or so we thought.
Now making the Internet rounds is a posting questioning whether McCain's presumptive Democratic opponent, Illinois Sen. Barack Obama is a natural-born citizen and therefore constitutionally qualified to be president. I suppose it was only a matter of time.
Anyway, this particular post, whose authorship is unclear, suggests that Obama is "not legally a U.S. natural-born citizen under to the law on the books at the time of his birth...". According to the poster, if only one parent was a U.S. citizen at the time of birth, the citizen-parent "must have resided in the United States for at least ten years, at least five of which had to be after the age of 16." Obama's father, of course, was not an American citizen, having been born in Kenya. That leaves his mother, who was a natural-born citizen, but who was only 18 when Obama was born, on August 4, 1961. In the poster's opinion, Obama fails the constitutional test because his citizen-mother had not resided in the U.S. for five years after the age of 16--not old enough, at the time of Obama's birth, "to qualify her son for automatic U.S. citizenship."
Now pay strict attention, because I'm only going to explain this once: Is Barack Obama a natural-born citizen of the United States and therefore eligible to become president? The answer is yes, according to Ron Gotcher, a noted California immigration lawyer and The Swamp's resident expert on presidential eligibility.
"The poster's confusion," Gotcher writes, "is over the concepts of jus sanguinis and jus soli." Under jus sanguinis, a person's citizenship is transmitted "by the blood" - by inheritance from his or her parents or grandparents. In the United States, we recognize citizenship through parentage in a number of cases.
But it is not necessary to look to the statutes that deal with citizenship through jus sanguinis, since Senator Obama's citizenship derives from jus soli - citizenship through place of birth.
According to Gotcher, "The Fourteenth Amendment commands that "[a]ll persons born or naturalized in the United States , and subject to the jurisdiction thereof, are citizens of the United States and of the state wherein they reside."
"This was clarified by the Civil Rights Act of April 9, 1866, which provided that 'All persons born in the United States and not subject to any foreign power are declared to be citizens of the United States.'"
"Senator Obama was born in the State of Hawaii two years after it became a state on Aug.21, 1959 As such, he acquired United States citizenship automatically at birth. While it is not necessary to go into all of the other legal errors contained in the posting (and there are many), the simple fact is that, with rare exceptions (children of diplomats), everyone born in the United States is a citizen of the United States at birth."
http://www.swamppolitics.com/news/politics/blog/2008/06/is_barack_obama_a_us_citizen_y.html