I found it hard to explain my views on the causes of World War One and I'd like to see what some scholars might say that is short and to the point. Growing up, about the American civil war we learned "States rights, King Cotton, and Slavery". Is there a similar statement about WWI?
The shortest, simplest answer I can think of is: Germany knowingly supported Austria-Hungary in a local war, seeking an advantage in Europe, risking escalation into a much larger conflict, expecting that diplomacy would either limit or defuse the situation, as had happened in several previous flashpoints prior to WWI.
That's the inception of the whole thing. But really, any statement of this kind is incomplete, and lacking in the sort of details that really gets to the root of the problem. It wasn't just one factor, it was a whole host of interlocking causes.
Keeping in mind
The international system, customs, and biases established* in a fairly Christian Europe where powerful families ruled over stationary, low skilled peasants came into contradiction with the demands of the modern nation-state ruled by a meritocracy** of literate, secular-liberal citizens with the productive capacity of the scientific method and industrial capitalism.
*by the Treaty of Westphalia, the Congress of Vienna, and some others
**something approaching it, at least; obviously the potential of many classes of people was not yet tapped