It is in their interest to see that American students remain relatively uninformed as to their history; which is why we recently saw moves by some to refrain from teaching any American history occurring before 1870...when our nation was guided by God, laws and common sense.
Although there are many things wrong with our public school system. I see the rewriting, or dumbing down of American history as the big one that is most detrimental to America remaining a free nation.
Knowing what America stands for is not a genetic inheritance. It must be learned by the next generation, and the next, and the next. It must also be learned by the people that migrate into America. Our government schools are doing a piss poor job of teaching the fundamentals of American history, but are doing a wonderful job of teaching division rather than teaching all that unites us.
So that next generation is being taught America's flaws, and the text books ignore America's goodness. Instead of text books having true American history written in them, they are loaded with blatant liberal bias.
Is it any wonder many high school graduates can not explain the purpose behind the Declaration Of Independence, or explain how Congress and the Supreme Court check Presidential power. We can not blame them for not knowing these things, because they are not being taught them. Its just not politically correct anymore to do so.
The goal was to remove control of schooling from the parents, and place it in the hands of professional bureaucrats. Once this was accomplished our schools have become laboratories for social engineering experiments. The problem lies in, not that we have made a mistake, but the fact that many can't seem to see the mistake.