For example: one must take care in telling the history almost exclusively from the white settlers' persective over minorities perspectives, who are surely just as American. American kids should be able to identify with both the settlers and the minorities as their forebears. If you try telling parts of the story from the point of view of the native americans: their culture, how they saw the white settlers, what they were concerned about in their behaviour, then compare and contrast with settler goals and interests etc - then you can deal with the complexity and address the negatives without pointing fingers.
I'm not sure as to what degree America does this. My country (don't get me wrong it has a rich history in shitty behaviour) has approached education from this angle - and slowly leaked the bad history to kids, with more depth as they grow up. I found it a good way to slowly present it and we managed to handle it.