Depends on who you talk to. The purpose of the natural born citizenship clause was to ensure that any president had a connection and loyalty to the U.S. from birth.
If the prior reported statements are true (I too am cautious with Dr. Corsi, who claimed that a natural born citizenship meant being born on our soil, in the face of Marshall, Waite, Story, Hughes, Gray, and Congressman Bingham). Corsi's interpretation would enable the child of an illegal immigrant, anchor baby, to become president, but not Henry Kissinger or Schwarzenegger or Marc Steyn. If this statement is verified, the government seems to be saying to the courts, "Challenge him if you dare."
The Constitution never mentions "dual citizens." probably because it would have been unthinkable to have even considered citizenship for someone whose allegiance was not sole allegiance. Would that our military realized that allegiance to the Koran is a contradiction to allegiance to our Constitution; we would have eleven more living patriots and eleven intact families rather than families who know their government places a higher value on not offending nations who hate us than on the lives of its citizens.
A number of justices along with founder Dr. Ramsay and 14th Amendment author Bingham specify "sole allegiance" for citizenship, which is a super-set of natural born citizenship. If this state department memorandum is verified, many will look more carefully at the dicta (the comments which weren't essential to the judgment, such as John Marshall's famous citation of Vattel "born on the soil of citizen parents" in The Venus, 12 U.S. 253. (My latest count is twelve affirmations and no contradictions.) Since most of our Constitution rests upon our "common law" understanding of the meaning of words, the supreme court's evasion, as described recently by Justice Thomas, should end.
Remember Senator's Leahy and McCaskill in 2008, Senate Res. 511, saying “Because he was born to American citizens, there is no doubt in my mind that Senator McCain is a natural born citizen,” said Leahy. “I expect that this will be a unanimous resolution of the Senate.” It was! That was not an innocent statement. Yes,it was politcs, but let's leave that subterfuge for the moment. Leahy was citing his understanding. Every senator concurred, including Obama. That makes it part of common law. A a gray area remains because the common law interpretation has not been needed for a decision (though some expert might argue that it was in Perkin v. Elg, which I'll read again before commenting on). Leahy and every senator, albeit directed at the other candidate, McCain, repeated the 'jus sanguinis' part of the definition which was understood in most nations, and simply repeated in Vattel's Law of Nations. It is all about the allegiance of the parents.
Any parent will recognize the natural law origins of jus sanguinis - the inheritance of allegiance from parents. Through most of society a family examines the families of a marriage partner for their child before approving of a marriage. The parents, more than any other factor, tell about the beliefs, morals, ethics, and allegiances of the child. For the first nation to be built on ideas rather than bloodlines, ascertaining allegiance, as we are relearning the hard way, is critical to our survival. Credit to Charlie Rose and Tom Brokow for coming straight to the point with their now famous "What do we know about Barack Obama." Our Constitution required that we know that his parents swore allegiance explicitly, as naturalized citizens, or implicitly as native born citizens to our nation. Our nation, as Marshall explained, is a nation of laws, and not of men.