There has not been a serious challenge to the ruling in Wong since 1898. That!’s why it is settled law.
According to Westlaw, Wong Kim Ark has been cited in subsequent cases more than 1000 times. Now THAT’s “settled law.”
http://en.wikipedia.org/wiki/Westlaw
Perhaps it's time there was a challenge, as it contains rather serious factual errors in some of the assumptions that are stated.
Such challenges, however, wouldn't be necessary if we all would take the Supreme Court at their word:
"The question presented by the record is whether a child born in the United States, of parents of Chinese descent, who, at the time of his birth, are subjects of the Emperor of China, but have a permanent domicil and residence in the United States, and are there carrying on business, and are not employed in any diplomatic or official capacity under the Emperor of China, becomes at the time of his birth a citizen of the United States by virtue of the first clause of the Fourteenth Amendment of the Constitution"
And...
"The evident intention, and the necessary effect, of the submission of this case to the decision of the court upon the facts agreed by the parties were to present for determination the single question stated at the beginning of this opinion, namely, whether a child born in the United States, of parent of Chinese descent, who, at the time of his birth, are subjects of the Emperor of China, but have a permanent domicil and residence in the United States, and are there carrying on business, and are not employed in any diplomatic or official capacity under the Emperor of China, becomes at the time of his birth a citizen of the United States."