A significant number of teens didn't know who Osama Bin Laden was until we killed him. I can't believe it--and yet I do believe it. I didn't know what Iran Contra was when I was in high school, and I was a sophomore when it happened. Teenagers live in their own little world, only tangentially connected to the one the rest of us occupy. Today's high-school freshmen weren't even in Kindergarten when 9/11 happened. Why would they remember?