Heck, even basic psychology would point to this in human behavior.
One terrorist leader dies, more spring up as a result of the civilian deaths.
The way you fight these wars, isn’t to kill the enemy.
The idea is to discredit, delegitimize and drive the people to turn them in.
Guerrilla warfare has never ended because of fighting.
It has ended when the general population, outside of the extremists have been appeased, and the basic moral principles and interests of humanity have been settled.
The only way to stop a war of this nature, is to not subdue or eliminate your enemy, but to naturally have them uprooted.
Protect the homeland and citizens abroad from attack, if you can.
But don’t try to occupy or kill off people abroad, without first altering the policies to make up for the offenses that you may have actually done to other people.
Be reasonable in your giving, and acknowledge the mistakes that you’ve made.
And that’s not something that our President seems to do well, nor is it something that American leaders, in particular, seem to do/have done well either.
Think about it.