violations in which American civilians were killed. The German U-boat torpedoed the RMS Lusitania in 1915. It sank in 20 minutes, killing 128 American civilians and over 1,000 Britons. It was against the laws of war to sink any passenger ship without allowing the passengers to reach the life boats. American opinion turned strongly against Germany as a bloodthirsty threat to civilization. Germany apologized and repeatedly promised to stop attacks by its U-boats, but reversed course in early 1917 when it saw the opportunity to strangle Britain by unrestricted submarine warfare. It also made overtures to Mexico, in the Zimmermann Telegram, hoping to divert American military attention to south of the border. The German decision was not made or approved by the civilian government in Berlin, but by the military commanders and the Kaiser. They realized it meant war with the United States, but hoped to weaken the British by cutting off its imports, and strike a winning blow with German soldiers transferred from the Eastern front, where Russia had surrendered. Following the repeated sinking of American merchant ships in early 1917, Wilson asked Congress and obtained a declaration of war in April 1917. He neutralized the antiwar element by arguing this was a war with the main goal of ending aggressive militarism and indeed ending all wars. During the war the U.S. was not officially tied to the Allies by treaty, but military cooperation meant that the American contribution became significant in mid-1918. After the failure of the German spring offensive, as fresh American troops arrived in France at 10,000 a day, the Germans were in a hopeless position, and thus surrendered. Coupled with Wilson's Fourteen Points in January 1918, the U.S. now had the initiative on the military, diplomatic and public relations fronts. Wilsonianism—Wilson's ideals—had become the hope of the world, including the civilian population Germany itself. Involvement in Russia The U.S. joined with several Allies to intervene in Russia in 1918-1919. The U.S. military was strongly opposed, but President Wilson reluctantly ordered the action. The British had taken the lead and were emphatically urging American help. Wilson feared that if he said no he would undermine his primary goal of creating a League of Nations with full British support. The main British goals were to help the Czechoslovak Legion re-establish the Eastern Front. At times between 1918 and 1920 the Czechoslovak Legion controlled the entire Trans-Siberian Railway