I can't understand why members of the the Triple Entente and also members of the Triple Alliance were so offended by the mere mobilization of their enemies' armies, so that they demanded a cessation of mobilization or else they would declare war.

Why not simply decline to meet trouble half way, and match mobilization with mobilization, putting the ball back in the other nation's court, so to speak.

For example, Wikipedia: World War I says:

"The Serbian capture of ports on the Adriatic resulted in partial Austrian mobilisation on 21 November 1912, including units along the Russian border in Galicia. In a meeting the next day, the Russian government decided not to mobilise in response, unwilling to precipitate a war for which they were not yet prepared."

This quote seems to imply that to mobilize one's army, even partially, and only to match partial mobilisation with partial mobilization was tantamount to a declaration of war. I don't see why it should be.

And when Russia did eventually mobilize, Germany did declare war on Russia, rather than take the measured, defensive response of likewise mobilizing.

The Great War Series has "Why Did The First World War Break Out? (July Crisis 1914 Documentary)"

Youtube at 21:25 / 30:26 has

"[…] and thirty minutes later Germany announced their mobilization. By seven pm Moscow told Berlin that Russia would not stop its mobilization, and so Germany declared war on Russia."

I don't see how that follows.

Wikipedia: Mobilization#Mobilization in World War I which (interestingly, I think, but does not answer to my satisfaction the question I am asking), says:

"Intricate plans for mobilization contributed greatly to the beginning of World War I, since in 1914, under the laws and customs of warfare then observed (not to mention the desire to avoid compromising national security), general mobilization of one nation's military forces was invariably considered an act of war by that country's likely enemies."

So it's not a question of simply "Why didn't Germany do things differently on that day?" but rather, why was mobilization seen as an act of war by everyone at that time?

It seems to have contributed to the danger of war breaking out accidentally. It's not specifically about Germany, but that kind of thinking by countries back then, of which the German demand and subsequent declaration of war on Russia on 1st August 1914, when that demand was not met, is a well-known example.

  • 26
    The answer to all of the "why didn't Germany do something smarter in the runup to WWI?" questions tends to be "Because Kaiser Wilhelm II was a fool." Anyone who wasn't a sycophant had by this time been purged from his advisory circle. So even if he'd listen to someone saying "That's not a good idea" (he wouldn't), there was nobody around him who would say that.
    – T.E.D.
    Commented Aug 22, 2022 at 18:02
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    There were several mobilizations in the years preceding WWI. In particularly in France people got tired after a couple of them. By 1914 some of the store fronts had signs "Temporarily closed due to the annual mobilization." Doing that doesn't help with moral when the war starts for real.
    – Michael
    Commented Aug 23, 2022 at 15:58
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    To answer the title question, in 1914 Europe, you can't mobilize your army without notifying 10's or 100's of thousands of soldiers and reservists, changing railroad schedules, etc., so you can't hide it from your adversary. So your adversary will mobilize their army in response whether you declare war or not.
    – The Photon
    Commented Aug 23, 2022 at 16:24
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    The quote "Moscow told Berlin" sounds funny. In 1914 the capital was St.Petersburg, not Moscow. Is the video author avare of this?
    – Heopps
    Commented Aug 24, 2022 at 6:59
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    @Heopps It seems you are right. Wikipedia en.wikipedia.org/wiki/Saint_Petersburg says, "In Russia, Saint Petersburg is historically and culturally associated with the birth of the Russian Empire and Russia's entry into modern history as a European great power.[10] It served as a capital of the Tsardom of Russia, and the subsequent Russian Empire, from 1713 to 1918 (being replaced by Moscow for a short period of time between 1728 and 1730).[11] After the October Revolution in 1917, the Bolsheviks moved their government to Moscow." I have no idea whether the video maker knows about it. Commented Aug 25, 2022 at 1:49

3 Answers 3


Mobilization is hugely expensive

Industry slows down for the lack of workers, agriculture stops for the lack of horses.

It is not something a nation can afford to do lightly.

Speed of mobilization is critical

Germany and France had excellent rail networks, so they mobilized faster. On the other hand, Russia had bigger population resources, so, fully mobilized it would have a larger army (although with worse artillery) - but due to size and relative weakness of railways, it mobilized slower.

Once you draw, you shoot

All the war planners on all sides were blinded by their own excellent technology (conscript armies, magazine rifles, machine guns) and were confident that they were bound to win easily (forgetting that the adversaries had the exact same tech).

Thus it made no sense to them to mobilize (i.e., incur huge expense) and not go to war to justify that expense. Moreover, stopping mobilization "half way" was bound to put the whole transportation and logistical networks in a total disarray, making the country extremely vulnerable to attack in addition to incurring an immense cost.

Thus the German war plans did not even consider "partial mobilization" because they heavily relied on defeating France before Russia could finish its mobilization. The official thinking of the German General Staff was: as soon as Russia started mobilizing (even just "against Austria" as Russia declared) Germany "had no choice" other than to attack France as soon as possible because it stood no chance against both France and Russia fully mobilized (this answers the question in the title).

Note that in the end Germany did lose (despite forcing Russia to surrender), so it does appear reasonable that, if it did not try to take advantage of its shorter mobilization schedule, it would have lost even sooner (please do not consider this sentence "alternative history" ;-)

Prisoner's dilemma

In a way, this is a case of a prisoner's dilemma: all sides would have benefited from cooperation (defusing the situation and avoiding war) but no one trusted the others enough not to mobilize (prepare for the "inevitable defection" of the opponents), which killed all the remaining trust necessary for cooperation.

This, of course, is applicable to the "peace-loving forces" within the major players' governments. The above "cooperation-killing currents" made the war-mongers more powerful.

  • 1
    Quite right, the Axis was the weaker side and needed to knock out France quick if it was to win.
    – Ne Mo
    Commented Aug 22, 2022 at 23:28
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    @Ne Mo there was no axis in WWI.
    – Jan
    Commented Aug 22, 2022 at 23:34
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    I note that the generally used equivalent to "Axis" is "Central Powers" for WWI.
    – Mary
    Commented Aug 23, 2022 at 0:46
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    Maybe an aspect of honor played a role as well. To my knowledge, at the beginning of the war there still was an idea of chivalry: Formally declaring war before you undertake any aggressive move was seen as "the right thing to do". The horrors of World War I destroyed much of that. But I remember reading that a commander(?) of the attack on Pearl Harbor in WWII considered it shameful that the Japanese declaration of War hadn't been transmitted before the attack. It was planned to be transmitted minutes before the attack, but still before it. Commented Aug 23, 2022 at 8:53
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    The German mobilization also wasn't a static thing; the mobilization plan did not call for troops to be raised in place. The mobilization requirements could only be fulfilled with the troops in motion towards France, because units had to move through equipping points and clear transportation bottlenecks and then leave those spaces open for the next unit in line. John Keegan goes into some detail about this in his WWI work.
    – tbrookside
    Commented Aug 23, 2022 at 13:19

Germany strategically wanted a war

The strategic position of the German Empire prior to WW1 was complicated, with France on one side and Russia on the other.

The general strategy was to hope for a slow Russian mobilization that would allow the Germans to defeat France quickly, thus releasing forces to deal with the big but poorly equipped Russian army.

In this context, mobilizing the army without declaring war would have just given the opportunity to France and Russia to start mobilizing on their own, sacrificing Germany's head start and weakening its position.

  • Can you explain why NOT declaring war would result in slower mobilization in Russia? Seems like declaring war would increase the speed of mobilization in opposing countries.
    – DKNguyen
    Commented Aug 25, 2022 at 14:06
  • @DKNguyen No, what I mean is that Germany wanted to win its war with France before Russia was fully mobilized. Germany mobilizing but not declaring war would give more time to fully mobilize, so Germany had to attack ASAP.
    – SJuan76
    Commented Aug 25, 2022 at 18:00
  • I apologize. It still is not clear to me. I think I lack some understanding of what mobilizing and declaring war actually entails. It sounds like you can attack without mobilizing the army? And that to attack you must declare war?
    – DKNguyen
    Commented Aug 25, 2022 at 18:13

Aggression Wins Wars

In addition to the political and economic cost of "just" mobilizing (which you could theoretically justify mobilizing without war by saying "look at how our mighty host's assembly caused the enemy to back down!") there is also the military thinking of the era.

Though machineguns/gatling guns, rapid fire weaponry, breech-loading artillery, and smokeless powder (all part of the technological trap that made WWI so deadly) had all been used in war prior to WWI, European thinkers did not fully grasp their import. Wars in America and Asia, fought by "amateurs" and "lesser races" were not seen as definitive. The Franco-Prussian war (which admittedly had some of these new weapons) was seen as much more indicative of what would happen in a general European war. And the takeway from that war was that Speed Kills, and Offensive is All. The hesitant French were knocked onto the strategic defensive, stuck in fortifications, and handily beaten by the Prussians and their allies. Before that there was a similar quick decisive victory of the Prussians over the Austrians, and then before THAT the aggressive nature of Napoleon and other great european/western commanders.

For politicians and military commanders on all sides, there was a firm (and backed by recent historical facts) belief that the side that struck first and hardest would win. So partially mobilizing, waiting for your enemy to mobilize first, was seen as wildly dangerous to the point of it being a military and political nonstarter. And the truth of that is born out in the first few weeks of fighting. The German swing into France would have won any previous war, as would Germany's aggressive move towards the Russians at Tannenburg. The only fail was the Austro-Hungarians, but Conrad Von Hotzendorf is at best the second worst general of the war! It's only in hindsight you can see the massive resilience in million-man conscript armies which enables the war to roll on. Would everyone arming up and sitting at the borders have ended things peacefully? Maybe. But you can't fault them for their thinking because it's the same strategic though that's played out from ancient rome to the Russo-Ukraine war currently ongoing. The only difference is the advent of million-man consript industrial armies meant that the "leadup" was longer so you could watch the enemy make the first move (mobilize) and realize that you either had to beat them to the punch or take an existential risk by letting him get the first blow.

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