Austria-Hungary naturally harbored a fear of Russia and seemed to operate under the expectation that a Russian clash was as inevitable as a Serbian clash. Meanwhile, it seems that Russia, too, feared that Austria (with the backing of Germany) would draw them into armed conflict. The height of those concerns coincided with the winds of revolution beginning to blow across the Russian nation. The Tsar, born into leadership, may not have been prepared or capable of dealing with the extreme nature of the brewing situation. For Russia, it was a simple matter of backing/protecting their ally, Serbia. So, I cannot place the blame squarely on the Tsar or Russia, despite their major role in the overall war.
While Serbia was home to the Black Hand terrorist group responsible for the assassination of Archduke Ferdinand, there was never a precise official relationship established between that militant group and the Serbian government. Although Serbians feared for and hoped to protect their brethren living in the Austro-Hungarian Empire from persecution, it was clear that they were willing to accept certain measures of the ultimatum delivered from Austria after the assassination. Despite their opposition to various conditions of the ultimatum, Serbia appeared to present a show of good faith in accepting most of the demands. Perhaps Serbia, hoping that their "big brother- Russia would stand beside them in the face of war, only sought to appease the Austrian monarchy long enough to mount their own offensive. Whatever the case may be no such offensive was launched. In retrospect, while the deadly actions of a few Serbians may have in effect lit the fuse, it was other nations who a!.
ssumed the posture of war on behalf of Serbia while the Serbian government sought diplomatic solutions to the tensions. This view may be nave, but it leads me to say that Serbia was the least responsible for the outbreak of World War I.