For more information on the actual, sordid history of the American public school movement, google "The Underground History of American Education," by John Taylor Gatto. You can read it online for free.
In very terse summary, the American school system was imported from Prussia (that's northern Germany, for those of you who studied geography in public schools). The Prussian schools were designed--not to turn out highly-educated, competent, independent-thinking people--but barely-educated, obedient soldiers and factory workers. Above all, school was designed to inculcate obedience to political authority. People who were too smart were viewed as dangers to the established order.