We can't go on letting barbarians kill our people. We can either wage and win this war in our enemies' lands and (eventually) hearts and minds, or we can simply defend ourselves at home.
If we fight and win, we carry American values past our shores, and liberate trampled lands. If we retreat behind our borders and play defense, then we'll lose our American values -- freedom, privacy, trade -- in the attempt to make ourselves safe.
As a nation, we could probably become safe and neutral as Switzerland -- just with a bigger, fascist Army, and strip searches to get into the Post Office. But as a people, we could never accept the retreat and humiliation.
We can fight them there, or fight ourselves here. The choice is that stark. The outcomes are that drastic. It comes down to oppressive homeland security, or bashing the bad guys until they cry uncle.
I don't want to live in fear of them and of us. I want those who oppress to live in fear of us.