7.5 World War I: Military and Diplomacy

When World War I erupted in Europe in 1914, the United States initially maintained a position of neutrality, following its long-standing tradition of avoiding European conflicts. However, a series of events gradually pulled America into what would become known as the "Great War." The U.S. entry in 1917 helped tip the balance toward Allied victory and thrust America onto the world stage as a major power.

The sinking of the Lusitania. Image courtesy of History.com.

Causes of World War I: MANIA

The assassination in June 1914 was like lighting a match in a room full of gasoline. Countries quickly took sides based on their alliance systems. What started as a local conflict spread across Europe and eventually around the world as nations honored their promises to support each other.

The root causes of World War I can be remembered using the acronym MANIA:

• Militarism: European powers were engaged in an arms race, building up their military forces
• Alliances: Complex defense agreements meant any local conflict could escalate quickly
• Nationalism: Intense pride in one's nation led to competition and hostility
• Imperialism: European powers competed for colonial possessions and resources
• Assassination: The killing of Archduke Franz Ferdinand of Austria-Hungary by a Serbian nationalist sparked the war

The conflict quickly divided Europe into two main alliances:

America's Initial Neutrality (1914-1917)

America tried to stay out of the European war by declaring neutrality. Wilson urged Americans to be "impartial in thought as well as action." This policy made sense given America's distance from Europe and its tradition of avoiding foreign entanglements dating back to George Washington.

However, maintaining true neutrality proved difficult for several reasons:

• Economic ties: American trade with Britain and France was significantly larger than with Germany
• Financial interests: U.S. banks loaned the Allies about 2.5 billion dollars compared to only 56 million dollars to the Central Powers
• Public sentiment: German actions, as portrayed in American media, gradually turned public opinion against Germany
• British propaganda: British control of transatlantic cables allowed them to shape American perceptions of the war

Path to American Involvement

Germany's actions eventually made it impossible for America to remain neutral. The sinking of passenger ships, unrestricted submarine warfare, and the Zimmermann Telegram pushed public opinion toward war. Wilson's patience finally ran out in April 1917 when he asked Congress for a declaration of war.

Three major factors eventually pushed the United States toward war:

• The Lusitania Incident (1915): Germany's submarine warfare policy led to the torpedoing of the British passenger liner Lusitania, killing 128 Americans. Though the ship was secretly carrying munitions, the incident outraged Americans. Germany temporarily agreed to limit submarine attacks after U.S. diplomatic pressure.

• Resumption of Unrestricted Submarine Warfare (1917): In February 1917, Germany announced it would resume unrestricted submarine warfare, attacking any ships in the war zone, including those from neutral countries. This decision was a calculated risk that Britain could be defeated before America could effectively enter the war.

• The Zimmermann Telegram (1917): British intelligence intercepted and decoded a message from German Foreign Minister Arthur Zimmermann to Mexico, proposing an alliance against the United States. Germany offered to help Mexico reclaim territories lost in the Mexican-American War if the U.S. entered the conflict. When published, this telegram inflamed American public opinion.

Military Preparedness and Mobilization

America had to build a fighting force very quickly. The small peacetime army was not ready for a major war. The draft brought in millions of new soldiers, while factories switched from making consumer goods to producing weapons, ammunition, and supplies for the military.

When the United States entered the war, its military was woefully unprepared for a major conflict. The country quickly transformed itself for war:

• The Selective Service Act (May 1917) required all men aged 21-30 (later expanded to 18-45) to register for the draft
• Nearly 24 million men registered, and 2.8 million were drafted
• The regular army grew from about 128,000 to over 4 million by war's end
• Industry rapidly converted to war production

American Expeditionary Force (AEF)

General John J. "Black Jack" Pershing insisted on keeping American forces together rather than using them as replacements for Allied units. He wanted U.S. troops to fight as an independent army with their own identity and leadership, which helped establish America as a major military power.

General John J. Pershing commanded the American Expeditionary Force (AEF) in Europe. He insisted that American troops:

• Operate as an independent force rather than as replacements in British and French units
• Use aggressive, open-field tactics rather than the defensive trench warfare that had led to stalemate
• Maintain a distinct American identity while cooperating with Allied forces

The first American troops arrived in France in June 1917, but large-scale American involvement didn't begin until spring 1918. Key American military contributions included:

• Château-Thierry and Belleau Wood (June 1918): American forces helped stop a German offensive that threatened Paris, boosting Allied morale and demonstrating American fighting capability.

• Second Battle of the Marne (July 1918): American troops helped halt Germany's final major offensive and began pushing German forces back.

• St. Mihiel Offensive (September 1918): The first operation planned and executed under complete American command successfully reduced a German salient (bulge) that had existed for four years.

• Meuse-Argonne Offensive (September-November 1918): The largest American operation of the war involved 1.2 million American troops in a 47-day campaign that helped break German resistance. This brutal campaign cost 26,000 American lives.

The Fourteen Points and Peace Efforts

Wilson's Fourteen Points offered a new approach to peace. Instead of punishing the losers, Wilson wanted to fix the problems that caused the war. His plan included fair treatment for all nations and a League of Nations to prevent future conflicts through cooperation and negotiation.

As the war neared its end, Wilson outlined his vision for a just and lasting peace. In January 1918, he presented his Fourteen Points to Congress, which included:

• Open peace treaties instead of secret diplomacy
• Freedom of the seas
• Removal of economic barriers to trade
• Reduction of armaments
• Self-determination for nationalities (allowing ethnic groups to form their own nations)
• Creation of a League of Nations to preserve peace

Germany, facing imminent defeat, agreed to an armistice based on Wilson's Fourteen Points. The fighting ended on November 11, 1918, at 11:00 a.m. – the eleventh hour of the eleventh day of the eleventh month.

The Paris Peace Conference and Treaty of Versailles

Wilson faced tough opposition at the peace conference. Britain and France had suffered greatly during the war and wanted revenge. They forced Wilson to compromise on many of his ideals in order to create the League of Nations, which he saw as the key to lasting peace.

The resulting Treaty of Versailles included terms that can be remembered using the acronym BRAT:

• Blame: Germany was forced to accept sole responsibility for causing the war
• Reparations: Germany had to pay enormous financial penalties (about $33 billion)
• Armaments: German military forces were severely limited
• Territory: Germany lost its colonies and about 13% of its European territory

Wilson did secure the creation of the League of Nations, but had to compromise on many of his other points.

Senate Rejection of the Treaty

The treaty battle revealed a deep divide in American politics. Many Republicans feared that the League of Nations would drag America into future wars. Senator Lodge demanded changes to protect American independence, but Wilson refused to compromise and insisted on an all-or-nothing approach.

The Treaty of Versailles faced stiff opposition in the U.S. Senate, where a two-thirds majority was required for ratification. Opposition came from several sources:

• "Irreconcilables" opposed any involvement in European affairs
• "Reservationists," led by Senator Henry Cabot Lodge, supported the treaty with amendments to protect American sovereignty
• Concerns about Article X of the League of Nations covenant, which could potentially require the U.S. to take military action without congressional approval

Wilson refused to accept any compromises, insisting on an all-or-nothing approach. He suffered a severe stroke in October 1919 that left him partially paralyzed. Without effective leadership, the treaty failed to gain the necessary votes in the Senate. The United States never ratified the Treaty of Versailles and never joined the League of Nations.

War's Impact on America's Global Role

World War I changed America's place in the world, even as the country tried to avoid new commitments. The U.S. emerged as an economic powerhouse with a proven military capability. However, Americans remained divided about their global role, leading to a retreat into isolation during the 1920s despite the country's new power and influence.

Though the United States rejected the Treaty of Versailles, the war fundamentally changed America's position in the world. The conflict transformed the nation from a debtor country to the world's leading creditor, with European nations owing America over $10 billion.