The Constitution was pretty clear that this country was formed by those who fought for its independence and their children (”ourselves and our posterity”). The Constitution does not say for “ourselves and the babies born of those who wander into the country and knock up a local girl.”
pages 15-16
http://quod.lib.umich.edu/m/moa/AAT1053.0001.001/27?g=moagrp;rgn=full+text;view=image;xc=1;q1=vattel
Neither does it say a natural born citizen is a person born in this country whose parents were natural born or naturalized before said person’s birth. Doesn’t say it. Never has. Never will.