9/11 killed three thousand. WWII killed 50 million.
Though our response to 9/11 might have resulted in a million more killed, but we in the US had little awareness.
I said on 9/11/01, and I say today, we need the ability to respond to terrorist attacks proportionally and not let them get us to overreact and do bad things.
We'll probably never prevent a person from being able to go kill a bunch of Americans.
The most shocking thing is that it hasn't happened a lot more. We like to pretend it's because the government is preventing it, but they can't. No one can.
Of course the government can do a lot - but it can't prevent someone killing people.