Killing a bunch of folks certainly can lead to victory (see: Hiroshima, Nagasaki). One talking point I wish Trump would start hammering is that in order to win the war against Islamic terrorists, we have to DESTROY THEIR WILL TO FIGHT. That's what's been lacking in our efforts to date, but was at the very heart of our fighting in WWII. This war will go on forever if we only launch periodic tactical strikes intended to destroy some equipment here, or take out a leader or two there. What is needed, just as with imperial Japan, is to so shock and devastate the enemy that they simply don't want to fight any longer.
I know, that assertion would lead to some uncomfortable questions from the media about what such an effort would entail, but it is the one key point that is not being discussed, but which is absolutely essential to victory.
War is cruelty. There is no use trying to reform it; the crueler it is, the sooner it will be over.
— William Tecumseh Sherman
But we did that in Iraq. It got us nothing.