Force — naked violence was not used in either place, and we see the miserable outcome. 

Instead of nation building, if we went in and destroyed *everything*, there would have been a true peace, for a generation at least, and if we were still capable of using such force again, it would be easy enough to repeat the lesson. 

If you kill enough of your enemy, there is no one left to object to your methods, other than the weak men and women who fall under it's protective umbrella.