Europe 1917: United States Enters the War
With Russia crumbling, Germany moved to increase its pressure on the West. On February 1, it announced unrestricted submarine warfare in an attempt to starve Britain into surrender. This aggravated relations with the United States and, when German plans to incite a war between Mexico and the U.S. were uncovered, America declared war.
1 Feb 1917 Germany announces resumption of unrestricted submarine warfare▲
Germany announces resumption of unrestricted submarine warfare
1 Mar 1917 Zimmermann Telegram▲
In January 1917, German Foreign Secretary Arthur Zimmermann messaged Carranza's government in Mexico proposing an alliance between the two countries should the United States declare war. In exchange for Mexico's assistance against the US, Germany was prepared to recognize that country's reclamation of most the the land lost in the 1848 Treaty of Guadalupe-Hidalgo, as well as Texas. However, the effort backfired: Mexico declined the offer, concluding that its then-fractured military could not win against the US; and the telegram's publication decisively turned US public sentiment in favor of the Allies.
4 Mar–5 Apr 1917 Germany withdraws to Hindenburg Line on Western Front▲
Germany withdraws to Hindenburg Line on Western Front
8–12 Mar 1917 February Revolution▲
Mass demonstrations broke out in Petrograd, capital of the Russian Empire, in March (late February in the Julian calendar) in response to economic and social problems, compounded by the strain of World War I. After a few days, the mutinous Russian Army sided with the revolutionaries, forcing Tsar Nicholas II to abdicate in favor of a Provisional Government under Prince Georgy Lvov.
11 Mar 1917 Fall of Baghdad▲
After recapturing Kut on 24 February 1917 and defeating the Ottomans at the Diyala River on 10 March, the Mesopotamia Expeditionary Force under General Frederick Maude marches unopposed into Baghdad, the Ottoman regional capital. Although the Ottoman authorities had ordered the evacuation of the city the day before, some 9,000 Ottoman troops are caught in the confusion and became prisoners of the British.
6 Apr 1917 US declaration of war on Germany▲
On 2 April 1917, United States President Woodrow Wilson asked a special joint session of the US Congress to declare war on the German Empire. Congress obliged by declaring war on the 6th, with the resolution passing 82 to 6 in the Senate and 373 to 50 in the House.