Wow, this is a complicated question.
First off, maybe a little background about myself. I live in a country with the "old" educational system: the one where kids have to learn tons of useless facts. I've had eight years of history in school, and it was the subject I despised the most

. Second, my country has been through 3 (or four, depending how you count) wars in the 90's. And third, I'm a psychology major (and a major nerd, completely in love with what I study), so I'm interested in how people function.
Now to answer the question - I think it's reasonable to have history a subject in the regular school curriculum, but I think that the way it is taught is crucial. While I went to school, the messages in the textbooks kept changing yearly. The state had too much input into what will be taught, because a lot of ideology is taught through history classes. I do believe understanding history is very important, and I also believe there are lots of historians out there interested in the most objective interpretation available.
However, I don't believe in the power of this knowledge to prevent us from making serious mistakes. I have whitnessed a normal culture go barbaric, and - while everybody has the right to vote, once the voting is done, my impression was that very subtle decisions on the top of the government can make a huge difference with regards to the consequences. The average person usually does not recognize this, or does not want to spend their day analyzing subtle political messages.
That's my impression, anyway. I'm all for knowledge and education, but I still believe an elite has the final word. Now if we could get the elite to practice critical thinking...
(sorry for the not-so-subtle wording)