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Neutrality and intervention

In 1914 five European Great Powers went to war. How did this escalate into a 'world war' involving nearly all European countries and many internationally?

In 1914 five European Great Powers went to war; as did the smaller states of Serbia, Montenegro, Luxemburg, and Belgium. Because the European empires covered so much of the world, large parts of Africa, Asia, and Australasia also found themselves involved, although at first the non-European Great Powers were not participants, and much of Europe itself stood aloof. By 1917, in contrast, nearly all the European countries had become belligerents, as had Japan, Turkey, the USA, China and Brazil, and the war had impinged radically even on the countries that still remained neutral.

Intervention by Japan and Turkey

Intervention came in three waves, Japan and Ottoman Turkey coming first. Japan had been allied to Britain since 1902. As this was a defensive agreement, it was not obliged to intervene, but when the British requested naval assistance Japan’s Foreign Minister saw an opportunity to overrun Germany’s colonies in China and the North Pacific, which after declaring war on 23 August 1914 Japan duly did. Turkey, in contrast, secretly allied with Germany in August 1914 but entered the war only in October. The nationalist ‘Young Turks’ who dominated its government wanted to reverse two centuries of decline. They considered the German army the strongest in Europe and feared Russia, from which they suspected France and Britain would not protect them. Turkey’s entry massively extended the fighting, which spread to Gallipoli (where Allied forces in 1915 tried unsuccessfully to reach Constantinople), to the Caucasus, and also to Mesopotamia (now Iraq), Arabia, and Palestine.

Intervention by Italy

The second wave of intervention centred on Southern Europe. It began with Italy’s entry. Before the war Italy had been allied with Germany and Austria-Hungary, but in 1914 it did not join them. Its leaders wanted Italia irredenta: Austrian-ruled territories in the Trentino and round Trieste that Italian-speakers inhabited. They also wanted, for strategic reasons, the German-speaking South Tyrol and the Slovene- and Croat-inhabited coastline of Istria and Dalmatia, which the Allies promised them in the secret Treaty of London. Although the government justified intervention (May 1915) as completing national unification, socialists and Catholics opposed it, and Italy’s pro-war consensus was weak. Its involvement opened a new front in the Alps and along the river Isonzo, where the Austrians fended off Italy’s attacks in often appalling conditions.

Synopsis of our obligations to our allies and others

Map indicating Britain’s obligations to its Allies and others, included in a secret memorandum prepared in the British Foreign Office, 1918.

Map indicating Britain's obligations to its Allies and others, included in a secret memorandum prepared in the British Foreign Office, 1918. 

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Intervention by Bulgaria, Romania and Greece

None the less, Italy’s entry increased the pressure on the Austrians, and in autumn 1915 German troops assisted them in overrunning Serbia and its ally Montenegro, which Austria-Hungary had failed to accomplish unaided. Bulgaria, which resented Serbia’s control of Macedonia, simultaneously entered the war on Germany’s side. Allied forces tried to help Serbia by landing at Salonika (Thessaloniki), but arrived too late. Another stalemated front opened in the mountains north of the city. In August 1916, in contrast, Romania joined the Allies, who had promised it the Hungarian territory of Transylvania. But it too was quickly defeated and occupied. Finally the Allies brought in Greece in 1917, by intervening in Greek politics and backing the nationalist politician Eleutherios Venizelos against King Constantine, who wanted to stay neutral. All of the Balkan countries had now been drawn in.

Intervention by the USA

In the final wave of interventions, shipping and trade were central. Germany declared war on Portugal (March 1916), an ancient British ally, after it seized the German merchant ships in its harbours. But the biggest intervention was that of the US. President Woodrow Wilson had asserted neutral rights against the Allies (who were trying to cut off trade with the Central Powers) and the Germans (whose submarines attacked neutral shipping). In 1917 the US declared war on Germany over the submarine issue, though also because of a German offer to Mexico to ally against America and because of Wilson’s ambition to reform the global political system and create a League of Nations after the war. In turn American intervention encouraged others such as China and Brazil to follow suit.

Postcard of German zeppelin that crashed on Fanø

Postcard with photograph of a German zeppelin crashed on Fanø and crowd of civilian figures stood in foreground

Postcard showing the German Zeppelin L3 after it crashed on the Danish island of Fanø, 1915.

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Neutrality amid total warfare was a precarious condition, and the conflict began with a spectacular violation of Belgium, despite its status being internationally guaranteed. In many neutrals patriotic elites saw intervention as a chance to settle longstanding territorial claims, by launching parallel wars in regions remote from the main fighting fronts, although often these wars too became bogged down in trench campaigning. Sometimes fighting spilled over onto neutral countries’ soil or into their territorial waters and air space. Germany considered invading Norway and the Netherlands, although decided the costs would outweigh the benefits. In order to tighten their blockade the Allies controlled ever more strictly the trade of Germany’s neighbours: Norway, Denmark, the Netherlands, Switzerland, with food shortages and rationing as the consequence. By secret agreements they used Norwegian and Danish merchant ships in return for providing coal. Spain became polarized between liberal parties favourable to the Allies and conservatives who sympathized with the Central Powers. Even in countries that stayed out, the war caused economic hardship and political schism. It became a watershed for the neutrals as well as the belligerents.

  • Professor David Stevenson
  • David Stevenson is a Professor of International History at the London School of Economics and Political Science. He has published extensively on the causes, course, and consequences of the First World War. His books include 1914-1918: the History of the First World War; With Our Backs to the Wall: Victory and Defeat in 1918; and 1917: War, Peace, and Revolution. He is currently working on the British home front in 1916-17.