Italy’s entry into the First World War in 1915 and the USA’s intervention in 1917 transformed the conflict into a truly global war with profound consequences.
Italy’s Entry into the First World War, 1915
Italy’s Neutrality and Shifting Loyalties
When the First World War began in 1914, Italy declared neutrality despite its membership in the Triple Alliance with Germany and Austria-Hungary. Italy’s alliance obligations were defensive, and it argued that Austria-Hungary’s actions were aggressive. Italy’s government, under Prime Minister Antonio Salandra, began secret negotiations with both sides to gain the best territorial settlement in exchange for participation.
Key factors that influenced Italy’s eventual decision to abandon its former allies included:
Irredentism: A strong nationalist movement in Italy aimed to annex territories with Italian-speaking populations still under Austrian rule, such as Trentino and Trieste.
Mistrust of Austria-Hungary: Long-standing animosity and territorial disputes with Austria made alliance unity fragile.
Promises from the Allies: The secret Treaty of London (April 1915) offered Italy significant territorial gains, including South Tyrol, Istria, Dalmatia, and parts of the Ottoman Empire.
Domestic Political Pressures: Nationalist politicians, influential intellectuals, and sections of the public agitated for intervention on the Allied side, seeing it as a chance to complete national unification.
Treaty of London, 1915
The Treaty of London was the decisive factor. Negotiated in secret between Italy and the Triple Entente (Britain, France, and Russia), it guaranteed Italy:
Territorial Expansion: Recovery of contested Austro-Hungarian territories.
Colonial Promises: Influence and possible expansion in the Balkans and Ottoman lands.
Financial Support: Economic and military aid to sustain the war effort.
On 23 May 1915, Italy declared war on Austria-Hungary, officially joining the Allied powers. However, Italy did not declare war on Germany until August 1916, highlighting its primary focus on reclaiming territory from Austria-Hungary.
Escalation from a European to a Global Conflict
Colonial Theatres of War
The entry of Italy and later the USA broadened an already expanding battlefield. The European conflict had significant colonial dimensions:
Africa: Allied forces targeted German colonies, resulting in battles in Togoland, Cameroon, German South-West Africa (Namibia), and German East Africa (Tanzania). Local populations were drawn into the war as soldiers, porters, and labourers.
Middle East: The Ottoman Empire’s alliance with the Central Powers led to campaigns in the Dardanelles (Gallipoli), Mesopotamia (modern Iraq), Palestine, and Arabia. Notably, the Arab Revolt (1916–18), supported by Britain, sought to weaken Ottoman control.
Asia and the Pacific: Japan, aligned with the Allies, seized German territories in China (Tsingtao) and Pacific islands like the Marianas, Carolines, and Marshalls. Australian and New Zealand forces captured German Samoa and New Guinea.
Naval Warfare
Naval warfare was pivotal in globalising the conflict:
Blockades: Britain’s Royal Navy enforced a tight blockade of Germany, aiming to starve it of resources. This blockade extended to neutral countries, heightening tensions, especially with the USA.
U-boat Campaign: Germany countered with unrestricted submarine warfare, targeting Allied and neutral shipping to disrupt supply lines. This campaign was instrumental in drawing the USA into the war.
Naval Battles: Engagements such as the Battle of Jutland (1916) showcased the importance of naval supremacy but failed to decisively break the stalemate.
The global reach of these naval operations impacted trade routes, colonial economies, and civilian populations far beyond Europe.
The USA Enters the War, 1917
Causes of US Entry
After three years of neutrality, President Woodrow Wilson led the United States into the war in April 1917. Several intertwined factors explain this decision:
1. Unrestricted Submarine Warfare
In early 1917, Germany resumed unrestricted submarine warfare, sinking merchant ships without warning in the Atlantic.
The aim was to cripple Britain’s supply lines and force a quick Allied surrender before American mobilisation could influence the battlefield.
High-profile incidents like the sinking of the RMS Lusitania in 1915 (with 128 American deaths) had already strained US-German relations.
2. The Zimmermann Telegram
In January 1917, British intelligence intercepted a secret message from German Foreign Secretary Arthur Zimmermann to Mexico.
Germany promised Mexico financial support and the return of lost territories (Texas, New Mexico, and Arizona) if it joined the war against the USA.
Publication of the telegram enraged American public opinion and undermined isolationist arguments.
3. Economic Interests
By 1917, American banks and businesses had lent vast sums to the Allies. An Allied defeat threatened these investments.
Trade with the Allies far exceeded that with the Central Powers, making economic neutrality practically impossible.
American industrialists and farmers benefitted from wartime demand, creating vested interests in an Allied victory.
4. Ideological Reasons
Wilson framed US involvement as a mission to “make the world safe for democracy.”
He believed a democratic peace settlement required American participation to shape the post-war order.
Declaration of War
On 6 April 1917, Congress declared war on Germany, marking the USA’s formal entry into the conflict. The US would later declare war on Austria-Hungary in December 1917 but not on the Ottoman Empire or Bulgaria.
Consequences of US Intervention
Military Impact
The American contribution was decisive in shifting the balance in favour of the Allies:
Manpower: By mid-1918, over a million US troops were deployed in Europe, providing fresh forces at a time when European armies were exhausted.
Material Support: American factories supplied vast quantities of munitions, food, and equipment, sustaining the Allied war effort.
Morale Boost: The arrival of the “Doughboys” bolstered Allied morale and signalled to Germany that total victory was impossible.
The influx of American troops helped repel the German Spring Offensive of 1918 and facilitated the Allied counter-offensive, leading to the Armistice on 11 November 1918.
Economic and Diplomatic Consequences
Beyond the battlefield, American entry had far-reaching implications:
Financial Power: The USA became the principal lender to Britain and France, transforming it into a global financial leader. This shift foreshadowed the decline of European economic supremacy.
Wilson’s Fourteen Points: President Wilson sought to shape the peace through principles like self-determination and the creation of the League of Nations. Although not all his ideas prevailed, they influenced the Treaty of Versailles.
Redefining International Relations: The US intervention demonstrated its emergence as a world power with the capability and willingness to project influence abroad.
Isolationist Backlash: Post-war, American disillusionment led to a retreat into isolationism, exemplified by the Senate’s refusal to join the League of Nations.
Long-Term Impact
The globalisation of the First World War reshaped international politics:
Shift in Power: Europe’s pre-eminence waned as the USA and, to an extent, Japan gained prominence.
Colonial Repercussions: The mobilisation of colonial subjects sowed seeds of future independence movements.
Precedent for Total War: The war set new standards for global mobilisation, economic warfare, and propaganda, shaping the nature of 20th-century conflicts.
In sum, the entry of Italy and the USA broadened the war’s scope, deepened its global character, and decisively altered its course and legacy.
FAQ
Italian public opinion in the years leading up to 1915 was divided but increasingly shaped by nationalist voices demanding the completion of Italian unification, known as Italia Irredenta. Influential nationalist intellectuals, newspapers, and political figures argued passionately that Italy should seize the chance to reclaim regions like Trentino, Trieste, and Istria from Austria-Hungary. Large pro-war demonstrations, orchestrated by nationalist groups such as the Italian Nationalist Association, exerted pressure on an initially reluctant government. Anti-Austrian sentiment ran deep, rooted in historical conflicts and perceived betrayals by Vienna. However, significant sections of the public, particularly socialists and Catholics, opposed intervention, fearing the economic and human costs. Prime Minister Salandra’s government navigated this divided climate by negotiating secretly with the Allies while using propaganda to sway public sentiment towards intervention. Ultimately, the promise of national prestige and territory, amplified by nationalist rhetoric, outweighed pacifist resistance, tipping public opinion just enough to justify entering the war.
After joining the Allies in 1915, Italy’s military encountered severe challenges that exposed strategic miscalculations and logistical shortcomings. Firstly, the mountainous Alpine and Isonzo frontiers where Italy confronted Austria-Hungary were extremely difficult terrain for offensive warfare. Italian forces, under Chief of Staff Luigi Cadorna, launched repeated frontal assaults, especially along the Isonzo River, resulting in huge casualties with minimal territorial gains. Secondly, Italy’s military was underprepared and poorly supplied; the army lacked adequate artillery, munitions, and modern equipment compared to its more industrialised adversaries. Trench conditions were harsh, with soldiers suffering from cold, disease, and poor rations. Command structures were rigid and often incompetent, with Cadorna’s harsh discipline creating low morale and desertions. Furthermore, Italy’s economy struggled to sustain a prolonged war effort, exacerbating supply issues and creating civilian shortages. These military challenges culminated in disastrous defeats like the Battle of Caporetto in 1917, which forced Italy to reorganise its command and rely more heavily on Allied support.
The entry of the USA into the First World War in 1917 had profound implications for German military strategy. Aware that American manpower and resources would gradually tip the balance, German High Command, under General Ludendorff, opted for a decisive offensive to force a favourable outcome before US forces could deploy in full strength. This led to the German Spring Offensive of 1918, a series of ambitious attacks aimed at breaking Allied lines and capturing Paris. Initially, the offensives achieved territorial gains, exploiting surprise and stormtrooper tactics, but at a devastating cost in casualties and supplies. As fresh American divisions arrived, the Allies absorbed these blows and launched powerful counter-attacks. The psychological impact was equally significant: German soldiers and civilians realised the war was unwinnable against the combined might of Britain, France, and an industrially potent USA. Consequently, German strategy shifted from seeking outright victory to hoping for an armistice before total collapse, setting the stage for the November 1918 surrender.
Even before deploying troops, American financial and industrial contributions were crucial to sustaining the Allied war effort. From 1914, US banks, particularly JP Morgan & Co., arranged extensive loans to Britain and France, allowing them to purchase weapons, ammunition, and raw materials vital for trench warfare. This financial lifeline ensured the Allies could continue large-scale military operations despite their own economies being drained by years of fighting. American factories massively expanded production of steel, vehicles, rifles, artillery shells, and food supplies, helping offset severe shortages on the Western Front. The US also provided essential commodities like wheat, oil, and cotton, which kept both military and civilian sectors functioning in Britain and France. Transatlantic shipping networks, though threatened by German U-boats, facilitated the steady flow of goods. These financial and industrial measures made the USA an indispensable “arsenal of democracy” before its soldiers even crossed the Atlantic, and they entrenched economic ties that influenced post-war debts and reparations.
Global naval warfare during the First World War placed neutral countries in precarious positions, dramatically affecting their trade, sovereignty, and domestic stability. Britain’s naval blockade extended to goods bound for neutral ports like those in the Netherlands, Denmark, and Sweden, often forcing them to reroute or risk confiscation. This disrupted traditional trade patterns, causing shortages of essential goods and pushing up prices within neutral economies. Germany’s unrestricted submarine campaign endangered neutral shipping; vessels from the USA, Norway, and the Netherlands were sunk without warning, resulting in loss of lives and cargo. The threat of submarine attacks forced neutral countries to navigate complex maritime routes or seek convoys, raising insurance costs and limiting economic activity. Diplomatic tensions flared, particularly between Germany and the USA, as repeated sinkings like the Lusitania incident stoked public anger and influenced political decisions to abandon neutrality. Thus, naval strategies turned neutral waters into contested zones, challenging the very concept of non-involvement in an increasingly interconnected global conflict.
Practice Questions
Explain why Italy joined the First World War on the Allied side in 1915.
Italy entered the First World War on the Allied side in 1915 mainly due to nationalist aims and opportunistic diplomacy. Although bound to the Triple Alliance, Italy argued Austria-Hungary acted offensively. The promise of significant territorial gains under the secret Treaty of London was decisive. Italian nationalists sought to complete unification by acquiring Austro-Hungarian lands with Italian populations. Distrust of Austria-Hungary, domestic political agitation, and the belief that joining the Allies would elevate Italy’s status as a Great Power motivated this shift. Consequently, Italy declared war on Austria-Hungary in May 1915.
Assess the main reasons why the USA entered the First World War in 1917.
The USA joined the First World War in 1917 primarily due to Germany’s unrestricted submarine warfare, which threatened American shipping and lives. The sinking of vessels like the Lusitania increased anti-German sentiment. The intercepted Zimmermann Telegram, in which Germany proposed a German-Mexican alliance against the USA, further provoked public outrage. Economic interests also played a role, as American banks and industries were deeply invested in an Allied victory. President Wilson’s ideological commitment to safeguarding democracy and shaping a fair peace settlement also influenced the decision, making American entry both strategic and moral.
