Studies by German scholars show that the initiatives pushing Austria to issue ultimatums and invade Serbia came from the German Kaiser's staff.
The alliances then took effect, with Russia mobilizing to defend Serbia and Germany mobilizing to invade... France!
The French responded, and the Brits, and the Great War was on.
But the plot was hatched in Berlin and pushed by the Kaiser's High Command.
David Fromkin: "Europe's Last Summer, Who Started the Great War in 1914?"
No doubt the Kaiser was warmongering... but I[’m merely pointing out that when you have a people with a wounded national pride (the French emperor Napoleon III was hauled back as a prisoner publicly after the disastrous battle at Sedan, for one thing, the humiliating loss of Alsace-Lorraine, another) and you’re teaching a couple of generations of schoolkids that the hated Boche are the root cause of all of your ills and woes, it doesn’t take much to make a spark into a conflagration. They were itching for a fight, and they got one.
NOT letting the Kaiser off the hook here, merely pointing out that if it wasn’t the assassination of Archduke Frankie and his wife, it would have been something else.
Check out Alistair Horne’s book The Price of Glory. He goes into a lot of detail of the pre-war mindset of the French and the Germans. One gets the impression of the two biggest mouths on the block; sooner or later, they’re going to meet up.