Question

How did the buildup of militaries help lead to war?

Answer 1

Don't know which war to are referring to. But generally speaking. When a country has a large army, they plan to use it.

Answer 2

The Great War

Answer 3

That would be WWI to most Historians.
So the answer remains true. Lots of European countries with colonies all over the world were planning on a war they thought would surely happen. So everybody made treaties with everybody else and built up their armies for when the war happened.
A world leader is assassinated and Germany used it as an excuse to invade the low countries and France.
Everybody decided which treaties to honor, and the war was on.

Answer 4

thanks :)