War Guilt Methodology: Was Germany solely to blame for WWI?

Germany and Austria are to mainly blame for the outbreak of World War I.

The reasons are:

(1) The "carte blanche" Germany gave to Austria for attacking Serbia.

(2) The German "Schlieffen-Plan" - attacking France via neutral Belgium and Luxemburg, without declaring war on Belgium.

(3) The German long-term economical and political aims that were to be achieved by the war. Austria is to blame for taking the murder of the successor to its throne by a Bosnian Serb as a welcome occasion to end the undermining of the multinational Austro-Hungarian state by starting a war.

Source: Julikrise und Kriegsschuld, Bundeszentrale für politische Bildung

The answer, of course, is that no single country can be blamed for a catastrophe as large as World War I. This argument is made at length by Christopher Clark's The Sleepwalkers, which some in the international relations community consider to be the new standard account of the causes of WWI.

Clark starts with a structural approach to WWI, and adds to it with (I think) an excellent understanding of how flawed and sometimes irrational leaders (Wilhelm and Nicholas don't come off well here) led to bureaucratic mis-function and bad organizational decision making:

[Clark] concedes the importance of basic structural causes, such as rigid alliance commitments; the temptations of preventive war on a rapidly growing, militarized continent; and the peculiarities of authoritarian decision-making. Yet he believes that such forces alone cannot explain the war and might just as likely have led to peace. He argues that war emerged from a complex conjunction of factors, each of which was far from inevitable and in many cases even improbable, often because it involved decision-makers who behaved less than fully rationally. They indulged in illusions of power, stereotypes about their enemies, and outmoded conceptions of sovereignty; they succumbed to the demands of transient domestic coalitions; and they misperceived their surroundings, sometimes for no good reason. In all of this, such leaders were sleepwalkers, generally unaware of the horrific consequences of the war they were about to unleash. (source)

How much blame does Clark put on Germany?

[Clark puts] a stake through the heart of a common narrative that has Germany mobilizing first so as to spring the preventive war its generals had long advocated. It didn’t. Clark documents how Berlin’s political and military leaders stuck to their blithe belief that any conflict could be localized. Russia’s ­mobilization, he says, was “one of the most momentous decisions of the July crisis. This was the first of the general mobilizations.” (source)

There is plenty of blame to go around in Clark's account, much landing on key figures in Russia, Serbia, France, and England as well as Germany and Austria-Hungary. Perhaps the most tragic aspect of Clark's work is he concludes that the war was not inevitable--and by implication, neither was WWII, the Holocaust, Hiroshima and Nagasaki, and so on with the litany of 20th century horrors.

An aside: if you follow the NYT link, you'll see mention that Tuchman in Guns of August misdated Russia's mobilization as two days later than it actually occurred.

I understand that writing "any historians" you mean "any non-German historians". I think this questions is quite general; for everyone it is clear that Germany cannot be the one responsible, even declaring war both on Russia and France. In many sources it is clearly stated that Article 231 was unjust for Germany and thus an indirect reason of WW2.

I found some examples of "Allied" historians being "not sure" about German sole responsibility.

There is a nice study in the book Great War of the French (I read it in Polish translation) about the guilt of the war, I think at least one chapter, but can't remember at the moment. The rest of the book is entirely about France, her politics, military, economics etc.

In this study, the author presents his discussion with some German historian (I can't recall his name) and conclusions they made. As France's point of view (like the Revanche) was strongly affected by the German attack in 1914, and earlier in provoked war of 1870, lost of Alsace etc., this study seems to be very neutral and Duroselle accepted some arguments of this German historian. I'm sure they both agreed that Germany can not take the sole responsibility for the war (but this doesn't mean that there were no German activity leading to the war).

However, I don't remember, whom they blamed for the war; I'm however almost sure that this responsibility (in their opinion) was spread, as other historians do.

In the Dreadnought by Robert K. Massie the British-German naval competition is the main subject. The British two-power standard, even if not directly declared by author as unfair to Germany, is clearly shown as some reason of the Great War.

It is really, really hard to assign guilt or blame like this in most wars. I think in some ways we are spoiled by World War II, it being about a classic evil mastermind trying to take over the world and all, who kept taking over land and countries until it was clear that the best diplomatic efforts of everyone else had failed. That's just not how most wars work. Most of the time, most all of the belligerents have some sort of casus belli ("just cause") for the war, and most of the time, most all of the belligerents had some option they could have turned to besides war.

That being said, the Great War is one of those conflicts which in retrospect was all but inevitable, and to me it's hard to blame one country for starting something that was going to happen sooner or later anyway. My reasoning:

• It had been a long, long time since the continent was last embroiled in a major war. I don't think it's quite proper to compare world conflict to seismology, but in a sense there is a parallel here. The last big knockdown dragout conflict in Europe as of 1914 occurred a century previously at the Battle of Waterloo. There had been relatively minor or at least localized affairs since then (the Crimean War, the Franco-Prussian War, the Italian War of Independence) but nothing that hit the entire continent at once. By this point, nobody alive remembered how bloody the Napoleonic Wars were, and for many nations (France in particular) the notion of war had once again been wrapped in glory rather than loss and suffering.

• Alliances. The above was by design, of course; nobody wanted another Napoleonic War. The way this got resolved in practice was that everyone formed alliances with virtually everyone else, both by the old-fashioned "hey, marry my daughter" way (see: England and Russia) and by codified mutual defense treaties. If you wanted to invade Austria, Austria could call its allies and pretty soon the entire continent would be fighting you. It was something like mutually assured destruction in the Cold War. The downside of this was that once you did get the alliances moving, they were hard to stop.

• Increased militarization by all parties involved. As was noted above, France was really stung by the loss of Alsace and Lorraine as well as the ego drop that came with the Franco-Prussian War, and for many in that country it was not a matter of if but when they would try to win their fortunes back. Germany's escalation of armament can almost be seen as a reaction to this. Russia and England may have been more on the periphery of this but they were hardly silent.

• It was clear that some of the European nations were paper tigers. In addition to having way more trouble in the Balkans than a nation her size should have had, Russia in the early 1900s became the first European power to lose a straight-up war against a non-Western power in quite some time when it lost the Russo-Japanese conflict. The Austro/Hungarian Empire was also teetering in its own right; it is no coincidence that the horse that kicked over the lamp that started the war was located in areas nominally controlled by that once-great empire. And the Ottomans were also a shadow of their former selves. There were clear imbalances of power, and someone was bound to try and take advantage of that.

• It was a time of great turmoil in general. I highly recommend the book The Proud Tower by Barbara Tuchmann, which goes into some depth about the political issues surrounding the 25 years prior to the Great War. In many ways, the entire continent was one great tinderbox waiting to catch fire one way or the other. Anarchists had murdered several heads of state during this time, several countries had fallen into open revolution or were threatening to do so... a case could be made that if it weren't for the jingoistic effects of a great war, Europe in the 1910s could have witnessed several brutal civil wars instead. In a sense, the Great War encompassed some of these (primarily the Russian Civil War) and circumvented several others (the dissolution of Austria/Hungary and the Ottomans most of all). I'm not saying the Great War was a better result, but given the state of the times, it was an understandable one.