Topic 7.5 Notes – World War I: Military and Diplomacy

Why the United States Entered World War I

World War I began in Europe in 1914 because of militarism, alliance systems, nationalism, imperial rivalry, and the assassination of Archduke Franz Ferdinand by Gavrilo Princip. One crisis in the Balkans spread fast because the great powers were already armed and tied together.

The Central Powers were Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria. The Allies were Great Britain, France, Russia, later Italy, and then the United States.

Wilson declared neutrality in 1914. That did not mean the U.S. was uninvolved in the world. After the Spanish-American War, the U.S. was active overseas. The real issue was avoiding direct entry into a European war.

Many Americans liked neutrality because:

• Europe felt far away, and the U.S. had a strong antiwar tradition in European conflicts.
• The country was ethnically diverse, so people had different loyalties.
• Many saw the war as the result of old European power politics, not an American cause.

Neutrality got harder to keep because American trade and loans favored the Allies. Britain’s blockade made trade with Germany difficult and also shaped the news Americans received. Many Americans also felt more cultural sympathy for Britain and France than for Germany.

The immediate path to war

1. German U-boats attacked ships and challenged neutral rights.
2. The Lusitania sank in 1915, killing 128 Americans.
3. The Sussex incident in 1916 led Germany to issue the Sussex Pledge, promising limits on submarine attacks.
4. Germany resumed unrestricted submarine warfare on February 1, 1917.
5. The Zimmermann Telegram proposed a German-Mexican alliance and promised Mexico Texas, New Mexico, and Arizona.
6. The Russian Revolution removed the tsar, making the Allied side easier for Wilson to describe as democratic.

Wilson asked Congress for war on April 2, 1917, saying “the world must be made safe for democracy.” He framed the war as a defense of democracy, humanity, and neutral rights. Congress declared war on Germany on April 6, 1917, and on Austria-Hungary in December.

A couple names matter here. Theodore Roosevelt backed the preparedness movement, and Wilson’s 1916 campaign was tied to “He kept us out of war.” Also, the U.S. entered as an associated power, not a formal Allied member.

How the United States Helped the Allies Win

Once the U.S. entered, the biggest challenge was mobilization. America was not ready for a huge war in 1917.

• The Selective Service Act of 1917 created the draft.
• About 24 million men registered, 2.8 million were drafted, and 4.7 million served.
• The convoy system with naval escorts helped protect ships from submarines.

The American Expeditionary Forces

The AEF was led by General John J. Pershing, who wanted Americans to fight as an independent army when possible. That mattered because it gave the U.S. more military and political influence.

African American soldiers served in a segregated military. The 369th Infantry Regiment, the Harlem Hellfighters, fought with distinction under French command.

Soldiers of the 369th Infantry Regiment, the Harlem Hellfighters

Major combat in 1918

• Château-Thierry and Belleau Wood helped stop the German advance.
• Second Battle of the Marne helped turn the war toward the Allies.
• St. Mihiel Offensive was a major U.S.-led attack.
• Meuse-Argonne Offensive was the largest American operation of the war.

The best judgment for APUSH is this. The AEF fought only in the final phase, so its combat role was limited compared with years of European fighting. But U.S. troops, supplies, loans, and morale mattered a lot after Russia exited through the Treaty of Brest-Litovsk. Germany’s spring offensive failed, and the armistice came on November 11, 1918.

Wilson’s Peace Plan and the Treaty of Versailles

Wilson’s Fourteen Points aimed to build a stable peace, not just punish Germany.

Core ideas

At the Paris Peace Conference in 1919, the Big Four were Woodrow Wilson, Georges Clemenceau, David Lloyd George, and Vittorio Orlando. Wilson wanted an idealistic peace. France wanted security and punishment. Britain wanted balance and empire. Italy wanted territory.

The Treaty of Versailles mixed those goals:

• Article 231 blamed Germany for the war.
• Germany had to pay reparations.
• Its army was limited to 100,000.
• It could have no submarines or air force.
• The Rhineland was demilitarized.
• Germany lost territory and colonies.
• The League of Nations was included in the treaty.

Why the Senate Rejected the Treaty

Ratification required a two-thirds Senate vote, and Wilson made things harder by leaving key Republicans out of the peace process after Republicans won the Senate in 1918.

Two opposition groups formed:

• Irreconcilables rejected the treaty and League outright.
• Reservationists, led by Henry Cabot Lodge, wanted changes first.

The biggest fight was over Article X of the League covenant. Supporters saw collective security. Critics feared the U.S. would get dragged into foreign conflicts and that Congress would lose its power to declare war.

Lodge Reservations tried to protect U.S. sovereignty and congressional authority. Wilson then went on a speaking tour, suffered a stroke in 1919, and refused compromise. Senate votes in 1919 and 1920 failed, so the U.S. never joined the League of Nations.