In October 1914 the Ottoman Empire joined with Austria and Germany, by then known as the Central Powers. A German alliance permitted the Turks to renounce the limitations on Ottoman sovereignty imposed by Europeans in the nineteenth century and also to settle old grievances with Russia, the Turks’ historic enemy.

The entry of the Ottoman Turks pulled the entire Middle East into the war and made it truly a global conflict. While Russia attacked the Ottomans in the Caucasus, the British protected their rule in Egypt. In 1915, at the Battle of Gallipoli, British forces tried to take the Dardanelles and Constantinople from the Ottoman Turks but were badly defeated. Casualties were high on both sides and included thousands of Australians and New Zealanders.

The British had more success inciting Arabs to revolt against their Turkish overlords. The foremost Arab leader was Hussein ibn-Ali (1856–1931), who governed much of the Ottoman Empire’s territory along the Red Sea (see Map 29.1). In 1915 Hussein won vague British commitments for an independent Arab kingdom. In return, he joined forces with the British under T. E. Lawrence, who in 1917 led Arab tribesmen and Indian soldiers in a successful guerrilla war against the Turks on the Arabian peninsula. In the Ottoman province of Iraq, Britain occupied Basra in 1914 and captured Baghdad in 1917. In 1918 British armies, aided by imperial forces from Egypt, India, Australia, and New Zealand, smashed the old Ottoman state. Thus war brought revolutionary change to the Middle East (see “How did the Ottoman Empire’s collapse in World War I shape nationalist movements in the Middle East?” in Chapter 29).

Japan, allied with the British since 1902, joined the Triple Entente on August 23, 1914, and began attacking German-controlled colonies and territories in the Pacific. Later that year Japan seized Germany’s holdings on the Shandong (Shantung) Peninsula in China.

War also spread to colonies in Africa and East Asia. Colonized peoples provided critical supplies and fought in Europe, Africa, and the Ottoman Empire. More than a million Africans and Asians served in the various armies of the warring powers, with more than double that number serving as porters to carry equipment.

Many of these men joined up to get clothes (uniforms), food, and money for enlisting. Others did so because colonial recruiters promised them better lives when they returned home. Most were illiterate and had no idea of why they were going or what they would experience.

The war had a profound impact on these colonial troops. Fighting against and killing Europeans destroyed the impression that the Europeans were superhuman. New concepts like nationalism and individual freedoms — ideals for which the Europeans were supposedly fighting — were carried home to become rallying cries for future liberation struggles.

A crucial turning point in the expanding conflict came in April 1917 when the United States declared war on Germany. American intervention grew out of the war at sea and sympathy for the Triple Entente. At the beginning of the war Britain and France established a naval blockade to strangle the Central Powers. In early 1915 Germany launched a counter-blockade using the new and deadly effective submarine. In May a German submarine sank the British passenger liner Lusitania. More than a thousand people died, including 139 U.S. citizens. President Woodrow Wilson protested vigorously. Germany was forced to restrict its submarine warfare for almost two years or face almost certain war with the United States.

Early in 1917 the German military command — confident that improved submarines could starve Britain into submission before the United States could come to its rescue — resumed unrestricted submarine warfare. This was a reckless gamble. The United States declared war on Germany and eventually tipped the balance in favor of the Triple Entente.