Explain to them how politics in the US really work; how big corporations finance candidates who'll serve their purposes and that it's impossible to get elected without huge amounts of money from corporate and religious sources, necessitating that you support the interests of those groups at the expense of the interests of the US public, that the big news corporations toe the government line to avoid getting into trouble and having their profits hit, and that the US has a deeply nationalistic culture with disturbing parallels to fascist societies (oaths of allegiance, saluting the flag etc).
Also, you could explain to them that primary school teachers aren't exactly the brightest apples in the barrel. I remember them being as thick as shit when I was at school, and incapable of critical thought or understanding of subjects more advanced than finger painting and addition. They also used the kids as a captive audience for their own political and religious agendas. We had a teacher who was an active member of Greenpeace and who'd indoctrinate us with that stuff, and Christian head master who made us sing hymns and watch bible videos.
They might think you're mad, and decide to join the Bush youth and report you to their chapter leader, but you can't give them anything more than the truth.