The multibillion-dollar question, obviously, is: Did Austro-Hungary really had to declare war on Serbia (everybody in Vienna, Belgrade and everywhere else knew that there was no way in the world Serbia would accept the ultimatum so the war was a foregone conclusion when it was issued)?
The answer, unfortunately, is Yes. Yes, the Austro-Hungarian Empire had no other choice but to declare war on Kingdom of Serbia. Not doing so would have been to demonstrate a critical weakness which would have immediately resulted in more terrorist acts – and even in uprisings in the Imperial provinces on the Balkans – Croatia, Bosnia, Slovenia – and possibly even in other provinces.
The problem (of which both Vienna and Berlin have been well aware of) was that by declaring the war on the Kingdom of Serbia, the Austro-Hungarian Empire was inevitably starting the European War. The Great War in Europe. And as French and British colonies and dominions were to be automatically drawn into the war, the World War. The future First World War.
Why? Because there was no way in the world the Serbian government would have approved the Sarajevo assassination (and Apis for all practical purposes was the Serbian government in such strategic matters) without getting an approval guaranteed support from a very powerful external ally. And everybody in Europe knew who this ally was.
Russia. The Russian Empire. The largest and the most populous country in Europe (if not in the whole civilized world). With the largest army in Europe – by far.
Why did the Russian government approve of the plot that would have inevitably led the country into war with the Austro-Hungarian Empire (and, therefore, with Germany)? Because it had its own very compelling reasons for starting a new Great European War. And it was certain that it will be supported by two very powerful allies – France and the British Empire.
Why would the Russian empire want to start a new European war? First, there was the usual domination issue (‘the king of the European hill’). The Balkan hill for starters and later of the whole Europe – after the inevitable dissolution and destruction of the Austro-Hungarian Empire (that at the time was all but falling apart and needed just one external push) and weakening of its primary ally (Germany). Well, initially not the king by itself, but in an alliance with France and (to a lesser extent) with Britain, but still… well, you get the picture.
By June 1914, such an alliance (the so-called Triple Entente) has already been in existence for seven years. However, having an alliance was one thing, but convincing the allies to support the war with the Triple Alliance (of Germany, Austria-Hungary and the Kingdom of Italy) was quite another. How in the world did the Russian government managed to accomplish that?
With France, the job was relatively simple. It was enough (probably more than enough) to utter two key words: Alsace and Lorraine. After its defeat in the Franco-Prussian war of 1870-71, France lost these territories to Germany. And very obviously wanted them back.
No less obviously, the only way to get these territories back was through a new war with Germany and its allies. Which France – in partnership with Russia – fully expected to win. Especially with Britain joining the fun – and the latter had no other choice but to do so (because of the treaties between these nations and general aversion to German domination of the continent).
There was one more incentive for all three nations to go to war. The Ottoman Empire which was also falling apart and was, therefore, up for grabs. Russia wanted the Bosphorus and the Dardanelles straits that were vital for the Russian foreign trade (in 1914, about 80% of its exports went through these straits). And Britain and France wanted the Arab territories outside Turkey.
It is highly doubtful that Russia informed French and British governments about the Sarajevo assassination plot in advance; however, it did manage to convince both governments that if something like that would happen, both governments would support Serbia and Russia. Which they actually did!
The person responsible for this very impressive diplomatic achievement (and thus for the commencement of the First World War) was one of the most brilliant diplomats in Russian (and possibly European) history. Sergei Dmitrievich Sazonov.
Who had a skillful, energetic and devoted accomplice (more like lieutenant) in Belgrade, Russian ambassador to the Kingdom of Serbia Nicholas Hartwig (Baron Nikolai Genrikhovich Hartwig).
An ardent Pan-Slavist, Baron Hartwig was said to be “more Serbian than the Serbs” and in the period prior to World War I was thought by many to practically control the policy of the Serbian government (obviously sharing it to a significant extent with the “shadow government” of Colonel Dimitrijević and his Black Hand). However, for obvious reasons of military, economic and industrial might, the Black Hand was no less obviously a very much junior partner in this arrangement.
Interestingly enough, even anti-German propagandists (i.e., mainstream historians) admit that Baron Hartwig “may be seen as one of the causes of the war”. Well, yes – together with two other causes of this war – Russian Foreign Minister Sazonov and Serbian Colonel Dimitrijević. In this case, the cause of the war did have both first and last names – three of each.
The initial idea for the assassination plot most likely came from Apis (he was, after all, a professional in these matters). Probably long before actual assassination. During the so-called Saloniki trial, Apis confessed to the Serbian Military Court that he ordered the assassination of Franz Ferdinand in his position as head of the Intelligence Department and that the assassination was planned with the knowledge and approval of Nikolai Hartwig and the Russian military attaché in Belgrade Viktor Artamonov.
Which was very probably true (although the trial itself was… well, not up to the highest judicial standards). More like one of Stalin’s show trials (or the ‘main’ Nuremberg trial, for that matter). All defendants were found guilty of planning and executing the Sarajevo assassination. Apis and eight of his associates were sentenced to death; two others were sentenced to 15 years in prison.
These sentences, however, were considered quite a bit harsh, so the Serbian High Court reduced the number of death sentences to seven. Regent Alexander commuted four of the remaining death sentences, leaving just three death sentences in place.
Apis and two his closest associates were executed 26 June 1917 by a firing squad. Baron Hartwig very conveniently died on the 10th of July, 1914 (roughly two weeks after the Saraevo assassination), officially of a massive heart attack. Interestingly enough, while visiting the Baron von Giesl, Austrian ambassador to Belgrade.
The Serbian press immediately published several inflammatory articles accusing the Austrians of poisoning Hartwig while he was a guest at their embassy. Although he very well might be poisoned, the right place to look for culprits, must be, IMHO, a bit closer to home.
After the Russian Revolution of 1917, Sergei Sazonov emigrated to France (no surprise here). He died in 1927 in Nice. Interestingly enough, even some ‘mainstream’ historians place the blame for an early and provocative mobilization of Russian troops (which transformed the initially purely local conflict into a full-fledged European war) squarely on Sazonov’s shoulders.
Obviously, before giving their approval to the assassination plot, Hartwig had to clear it with his boss Sazonov and Artamonov – with his boss Major General Nikolai Yanushkevich (Chief of the General Staff of the Russian Imperial Army).
Which they obviously did – and Apis got their approval. And went ahead with his assassination plan. Which, in turn, triggered the chain of events which in just over a month started the First World War.
On 28 July 1914, Austria-Hungary declared war on Serbia. The very next day Russia unilaterally declared – outside of the conciliation procedure stipulated in the Franco-Russian military agreements – partial mobilization against Austria-Hungary. Which for all practical purposes was the same as declaring war on the latter.
On the 30th, Russia ordered general mobilization against Germany. Which again was essentially the same as the declaration of war. Consequently, contrary to the popular misconception, de-facto Russia declared war on Germany, not the other way around (which was only de-jure).
German Kaiser Wilhelm II asked his cousin, Russian Emperor Nicolas II, to suspend the Russian general mobilization. When the latter refused, Germany issued an ultimatum demanding the same thing plus a commitment not to support Serbia. Russia promptly refused again, so on 1 August Germany ordered general mobilization and declared war on Russia.
Did Germany had a choice? Was declaring war on Russia its only choice? Yes, it was, because by itself Austro-Hungarian Empire stood no chance against combined Russian and Serbian forces supported by inevitable French financial and other assistance.
And after the inevitable defeat of its ally, Germany by itself again stood no chance against combined Russian (on the Eastern front) and French (on the Western front) forces. So it had no choice but to come to the defense of Austro-Hungarian Empire. In other words, both nations were forced into the war – Austria-Hungary by the Sarajevo assassination and Germany by the Russian mobilization.
Hoping against hope to avoid war with France, Germany sent an ultimatum to France, demanding her not to support Russia, if the latter were to come to the defense of Serbia (which the latter essentially already did). France, apparently anxious to return Alsace and Lorraine (and to punish Germany for annexing them), responded by mobilizing its reserves, thus de-facto declaring war on Germany.
Germany responded by mobilizing its own reserves and implementing Aufmarsch II West (a modified version of the now famous Schlieffen Plan). Which was a sensible thing to do given that Germany and France were now de-facto in the state of war.
Following the directives of this plan, Germany attacked Luxembourg on 2 August and on 3 August declared war on France de-jure. On 4 August, after Belgium refused to permit German troops to cross its borders into France (not a smart thing to do, as it turned out), Germany declared war on Belgium as well.
Which gave Britain a desired casus belli. His Majesty government issued an ultimatum to Germany that Belgium must be kept neutral (which was impossible to accept if Germany wanted to win the war on the Western front – which it obviously did).
Germany replied; Britain considered the reply “unsatisfactory” (no surprises here) and on August 4th declared war on Germany. The First World War was now officially on. Courtesy of Russia, Serbia, France and Britain. Probably in this very order, although Serbia, Russia, etc. night also be a possibility.
True, all major (and probably some minor) European powers were consent with going to war. Some maybe even wanted it – for one reason or the other. But consenting to the war (and even wanting it) was one thing, but actually provoking it was quite another.
So the correct answer to the titular question is: The First World War was started by a very unholy alliance of Russia and Serbia (and some Yugoslav nationalists in Bosnia) assisted and supported by France and to a much lesser extent by Britain.
Therefore, the punishment of Germany stipulated in the Treaty of Versailles and administered by the victors was not only horrendously savage but totally unjust and unfair. No wonder Germans (all Germans, not just Nazis) developed a very powerful and irresistible (and very much understandable, if not justified) desire for revenge.
Which in just 20 years led to the Second World War.
The Essential Guide to Nazi Germany 