I see your point. Much of this vulnerability is psychological, though. If you look at how many people have died from terrorism in the past, it's not many, at least compared to things like cancer, heart disease or traffic accidents. Still, I remember how most Americans were more than happy to give up their freedoms and human rights after September 11, in order to fight terrorism. Never mind that those freedoms and human rights were probably much of the reason why the US became great (compare it to say Argentina or Russia). Ironically, I think in order to preserve freedom during periods of terrorism, we would have to do away with democracy, since most voters are such morons.