Ask open-ended questions that make them develop and express their thoughts. Compliment when they make a good or valid point - correct them when they state something as fact that's just not true.
Some possible 'talking points' to discuss:
"Wow, did you hear that Condoleezza Rice said on niteline that the U.S. never Said Saddam Was behind 9/11?"
http://story.news.yahoo.com/news?tmpl=story&u=/nm/20030917/pl_nm/iraq_usa_rice_dc&cid=615&ncid=1480or
"Donald Rumsfeld Sees No Link Between Iraq and 9/11?"
http://www.bayarea.com/mld/mercurynews/news/special_packages/iraq/6786561.htmor
Get a copy of the latest 'Vanity Fair' and ask them to read the article by Craig Unger that Dick Cheney Claims No Knowledge That White House Helped Evacuate 24 Members of the Bin Laden Family Days After 9/11
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Remember to TEACH them to think deeply and find out some things for themselves and not to rely on your opinion, or their parents opinion, or Faux News' opinion - they need to get their own (informed) opinion. If you teach them how to begin doing this, I think you will have given them all a wonderful gift!