You have to read the 14th amendment. PS: The language was intended to protect newly freed slaves.
(From The Daily Caller)
CBS News published an article on Wednesday that excluded the exact clause of the 14th Amendment that President Donald Trump cites to support his plan to end birthright citizenship. . . .
Critics of Trump’s plan point to the first clause of the 14th Amendment as proof that ending birthright citizenship would be unconstitutional, but Trump tweeted on Wednesday that the clause “subject to the jurisdiction thereof” gives him authority to do so.