Oh poop. Here's the bottom line which you seem to ignore - if we want to win a conflict, we have to be prepared to be more ruthless, more vicious, more merciless and more implacable than the enemy we face. Some say "you're stooping to their level". That's not quite true - we should be WORSE than our enemy. We should be so not because we enjoy it, or because that is our nature, but because that is what it takes to win. And in war, coming in second is not an option. An unpleasant fact and one we should consider BEFORE we commit to fight.
It's too late now. The only sane course of action is to follow through with what we started. Backing off will encourage our enemies and bring about attacks on our own soil which will make 9-11 pale by comparison.