There were monumental economic and political causes behind that war; without those "other" causes there might not have been a war at all.There is an important logical fallacy (see the section on Logic) called Post hoc, ergo propter hoc ("After this, therefore because of this").
You will have to determine which causes or effects you're going to write about.
The two strategic points you have to consider are (1) whether you're exploring causes or effects or both and (2) what is the order of the causes or effects you're going to pursue from least to most important or vice versa.
It is intriguing to explore the causes of some event that you always took for granted or to chronicle the effects of some phenomenon in society or nature.
It might be enough for your paper to point out causes or effects that people might not have thought of before, or to sort out those causes or effects so that people can grasp them with fresh insight or in a newly organized fashion.
On the other hand, your essay might lead to a call for action based on patterns of cause and effect that you have perceived.