Public school in the United States did not exist until the mid-1800s.  How, then, can it be the “cornerstone of democracy”?  Democracy was not established in public schools.  These days, it doesn’t flourish in public schools, either.  Have you not ever stopped to think who taught the creators of the Declaration of Independence to read?  Who taught the signers of our Constitution?     Democracy requires an educated people because this enables them to govern themselves.  It does not, obviously, require that people only be educated in public schools.