The root cause is always the people. People choose their govenments in any situation.
From the ones that allow the most freedom to the most restrictive dictatorships - those being governed are always in control because they always outnumber those in charge and if necessary they can rise up en masse and change it.
The reason they don't is because life isn't bad enough for them to want to personally risk dying to do so.
The point of war used to be to get the people in a country to decide that life was now so difficult that they should - in fact - change that government.
Now we do our best to make sure that those who allowed that government to exist in the first place are shielded from the effects of their decisions.