"All 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."
Let's remember the reason that this amendment was enacted in the first place, and why it did not become part of the Constitution at the beginning of the country, but only a century later.
After the Civil War, the nation and its government were filled with Southern reactionaries who had a hundred schemes to deny the vote to ex-slaves. Those who supported the destruction of slavery knew that these schemes would continue to be promoted until a sufficiently racist Supreme Court would give an okay to one of them*, and that would legalize the permanent second class status of blacks. Birthright citizenship was enacted not to create anchor babies, but to prevent white people from revoking the citizenship of blacks. It's existence can be totally traced back to the intransigent racism that still existed in this country after the Civil War, and which continues to this day. So, Republicans, if your absurd nightmare that millions of the wrong kind of people are going to come here and vote Democratic because of this were true, you would have nobody but your own God Damned racist, hate filled selves to blame. Suck on that, jerks.
*Too bad for them that they couldn't have held out until the current Supreme Court, which would probably accept a petition to classify ex-slaves as domestic farm animals.