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. For the reasons above stated, this court is of opinion that the question must be answered in the affirmative.[emphasis added]
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. For the reasons above stated, this court is of opinion that the question must be answered in the affirmative.[emphasis added]
Ummm, you missed an important factor in the decision in that permanent domicil and residence was necessary in order to meet the subject clause of the 14th amendment (see bolded part above). Gray spent quite a bit of the WKA decision on domicil and residence. Gray also distinguished 14th amendment citizenship as being different from natural born citizenship. The former, he said, is defined by the Constitution, while the latter is defined OUTSIDE of the Constitution. That latter definition was supplied in the Minor v. Happerset decision and affirmed in WKA, that a child born in the country to citizen parents was a citizen. The Minor decision rejected Virginia Minor's claim of 14th amendment citizenship because she was already a natural born citizen. Gray further affirms this by explaining that the Supreme Court was committed to the idea that the 14th amendment does not apply to those who are born in the country to citizens.
“becomes at the time of his birth a citizen of the United States.”
He can be a member of Congress. A president needs to be a natural born citizen. Rubio does not qualify.