I once saw a Twilight Zone episode where some people in a normal, everyday American town become convinced that aliens (the outer space kind, not the kind that get amnesty) have landed near their neighborhood. As time goes on they become increasingly paranoid, and as night falls they begin to turn on each other, even though nobody can be sure if they have actually seen an alien. The episode ended with two aliens observing the interaction of the humans, and they say something to the effect of "you see, we will just let them destroy themselves." I can't help but think we're doing them same thing sometimes in the war on terror. Victor Davis Hanson echos this sentiment here.