Militarism as a Cause of World War I: A Detailed Summary

MilitarismThe buildup or expansion of a country’s military power through recruiting more soldiers or building more weapons and vehicles. was one of the main causes of World War I, which began in July of 1914, following the assassination of Austrian Archduke Franz Ferdinand.  In fact, historians consider it to be one of four main long-term causes of the war, along with: alliance systems, imperialism and nationalism.  Militarism was a particularly important cause of World War I due to several key factors.  For instance, it caused nations to build up their armies and led to increased tensions between the European powers.  This was especially prevalent in the arms raceA competition where two or more countries each try to build a larger and more capable army than the other. and naval race that occurred between the European nations before the start of World War I.​

World War IMultiple ChoiceInteractive

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Historians identify four long-term causes of World War I. Which group below names all four correctly?

Tap an option.

Militarism, alliance systems, imperialism, nationalismMilitarism, assassination, imperialism, nationalismAlliance systems, imperialism, nationalism, industrializationMilitarism, alliance systems, nationalism, colonization

ExplanationHistorians group militarism, alliance systems, imperialism, and nationalism as the four long-term causes of World War I. The assassination of Archduke Franz Ferdinand was the spark that started the fighting, but it was a short-term trigger, not one of the four long-term causes.

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What Is Militarism?

Militarism can best be understood as the buildup or expansion of the ability of a country’s military to wage war.  This could be carried out by recruiting more soldiers for service or by building more weapons and vehicles for use in the army.  In the decades before World War I many European countries began to practice militarism and worked to expand and strengthen their military forces.  For example, there was an intense arms race and naval raceA competition between Britain and Germany to build more and better warships to dominate the seas. between several European nations in the buildup to World War I.

Specifically, France and Germany were heavily involved in an arms race in which each country doubled their armies between 1870 and 1914.  As well, there was a competitive naval race between Britain and Germany that centered around the construction of new naval ships.​

World War IDefinition

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Militarism

From Latin 'miles', meaning soldier

Militarism is the belief that a country should build up strong armed forces and be ready to use them to protect or expand its interests. Governments that follow militarism spend heavily on soldiers, weapons and warships, and military leaders gain great influence over national decisions.

"Between 1870 and 1914, France and Germany each doubled the size of their armies, an example of the militarism that helped push Europe toward war."

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Arms Race Before World War I

An arms race is when two or more countries compete to establish the larger and more capable armies.  France and Germany were heavily involved in an arms race in which each country doubled their armies between 1870 and 1914.  Both nations had a history of war against each other and their rivalry caused them to expand their military forces.  For example, the Franco-Prussian War had occurred just decades earlier from 1870 until 1871.  More specifically, Prussia (the largest Germanic Kingdom before the unification of Germany) defeated France in the Franco-Prussian War.  As part of its defeat, France gave up a section of its land called Alsace-LorraineA region of land France gave to Germany after losing the Franco-Prussian War, causing lasting French resentment., which bordered with Germany.  Germany’s control over Alsace-Lorraine was a major source of frustration for France and led to heightened tensions between Germany and France.  In fact, France had a deep mistrust of Germany in the years before World War I.​

This eventually led to Europe being carved up between two alliance systems – Triple Entente and the Triple Alliance.  Britain, France and Russia were the member nations of the Triple EntenteThe alliance of Britain, France, and Russia formed before World War I., while Germany, Austria-Hungary and Italy were the member nations of the Triple AllianceThe alliance of Germany, Austria-Hungary, and Italy formed before World War I..  The alliance systems alongside, France and Germany’s tensions caused each country to begin to build up their armies.​

At the outbreak of fighting in 1914, France had approximately 4 million soldiers while Germany had over 4.5 million.  This was significant because most other European countries did not have nearly as many soldiers at the ready to fight.  The arms race showed the distrust between the nations of Europe and when war did break out in 1914 it allowed the countries to go to war more easily.​

World War ICause & Effect

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Cause

Prussia defeated France in the Franco-Prussian War of 1870 to 1871 and took control of the Alsace-Lorraine region along the shared border.

Effects

France lost a strip of territory it considered its own, creating a lasting sense of national loss.

French distrust of Germany deepened steadily in the decades after 1871 and did not fade.

France doubled the size of its army between 1870 and 1914 partly in response to the threat it saw from Germany.

The bitterness over Alsace-Lorraine pushed France toward the Triple Entente alliance with Britain and Russia.

The loss of Alsace-Lorraine was a political wound that shaped French foreign policy for over forty years before World War I began. It made France far more willing to build alliances and expand its military as tensions with Germany grew.

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Naval Race Before World War I

The naval race of World War I was an important competition between Britain and Germany for naval supremacy.  Each nation raced to build more ships and capabilities, which led to an extreme increase in tensions between them.  As such, historians consider the naval race between these two major European nations to be a main cause of World War I.​

At the time, Britain had the largest navy in the world. Britain’s naval power was threatening to other European nations and caused many to build up their own naval forces.  Germany viewed the British navy as a threat and sought to develop its own navy to match.  Mostly Germany needed a strong navy to challenge British ships in the North Sea, which was located to the north of Germany and to the east of Britain.  The North Sea was Germany’s main route to the open ocean but was difficult for Germany since the North Sea was connected to Britain and the British navy dominated the area.​

One of the key areas that this naval race between Britain and Germany can best be seen is in the construction of new battleships referred to as ‘dreadnoughts’.  

The dreadnought was a class of battleship that existed in the timeframe of World War I.  However, the first dreadnought was the HMS Dreadnought from the British Royal Navy.  The name is meant to refer to a sense of ‘fearlessness’.  It was first launched in 1906, and completely changed the history of naval warfare at the time.​

February 10th, 1906

HMS Dreadnought Launched in the Naval Race Before World War I

The British Royal Navy launched HMS Dreadnought at Portsmouth on February 10th, 1906. The ship carried ten 12-inch guns and used steam turbine engines, making existing battleships obsolete and pushing Britain and Germany into a faster, costlier naval race that raised tensions across Europe in the years before World War I.

Source: Imperial War Museums© factsthatcrunch.com

How Did Militarism Cause World War I?

Militarism in Europe had a major impact on the start of World War I.  Historians have identified several ways in which militarism led to the start of the war.  First, militarism showed the rivalry that existed between the nations of Europe in the years before the outbreak of World War I.  When the nations of Europe competed in the arms race and naval race it led to increased tensions.  These tensions ultimately led to the start of World War I because it created an underlying feeling of distrust.  Also, militarism created the large forces that easily allowed the European nations to go to war in 1914.  If they had not built such large armies then the war may not have been so easy to begin and so devastating.  For instance, following the assassination of the Austrian Archduke Franz Ferdinand, which was the event that sparked World War I, the nations of Europe were able to go to war more easily due to their large armies.​

World War IImpactsInteractive

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The eventMilitarism as a Cause of World War I

Tap each impact to read what it led to.

1Rising Tensions in Europe2France and Germany Double Their Armies3Britain vs. Germany at Sea4Large Armies Made War Easier to Start5The War Became Far More Deadly

Rising Tensions in EuropeThe arms race and naval race showed the deep rivalry and distrust among European powers. Nations competing to build bigger armies and stronger navies created conditions where war became easier to start and harder to prevent.

France and Germany Double Their ArmiesFrance and Germany each doubled the size of their armies between 1870 and 1914. The loss of Alsace-Lorraine to Germany after the Franco-Prussian War drove French resentment and pushed both nations to keep expanding their forces.

Britain vs. Germany at SeaGermany wanted to challenge British control of the North Sea, its only coastal access. This rivalry pushed both nations to build larger and more advanced warships, raising tensions between two of Europe's most powerful countries.

Large Armies Made War Easier to StartBy the time Archduke Franz Ferdinand was assassinated in July of 1914, European nations already had massive armies ready to fight. Those large forces meant governments could mobilize quickly, which helped turn a political crisis into a full-scale war in a matter of weeks. | tank

The War Became Far More DeadlyBecause so many soldiers and weapons had been built up before 1914, the fighting that followed was far larger and more destructive than earlier European conflicts. Militarism did not just help start the war. It also made the scale of the killing far greater once fighting began.

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MLA: Beck, Elias. “Militarism as a Cause of World War I: A Detailed Summary.” HistoryCrunch, 28 September 2026, https://historycrunch.com/militarism-as-a-cause-of-world-war-i/.

APA: Beck, E. (2026). Militarism as a Cause of World War I: A Detailed Summary. HistoryCrunch. https://historycrunch.com/militarism-as-a-cause-of-world-war-i/

Chicago: Beck, Elias. “Militarism as a Cause of World War I: A Detailed Summary.” HistoryCrunch. September 28, 2026. https://historycrunch.com/militarism-as-a-cause-of-world-war-i/

Sources

• Margaret MacMillan, The War That Ended Peace.
• Hew Strachan, The First World War.
• Imperial War Museum
• John Keegan, The First World War.