<P> As U.S. President, it was Wilson who made the key policy decisions over foreign affairs: while the country was at peace, the domestic economy ran on a laissez - faire basis, with American banks making huge loans to Britain and France--funds that were in large part used to buy munitions, raw materials and food from across the Atlantic . Until 1917, Wilson made minimal preparations for a land war and kept the United States Army on a small peacetime footing, despite increasing demands for enhanced preparedness . He did however expand the United States Navy . </P> <P> In 1917, with Russia experiencing political upheaval following widespread disillusionment there over the war, and with Britain and France low on credit, Germany appeared to have the upper hand in Europe, while the Ottoman Empire clung to its possessions in the Middle East . In the same year, Germany decided to resume unrestricted submarine warfare against any vessel approaching British waters; this attempt to starve Britain into surrender was balanced against the knowledge that it would almost certainly bring the United States into the war . Germany also made a secret offer to help Mexico regain territories lost in the Mexican--American War in an encoded telegram known as the Zimmermann Telegram, which was intercepted by British Intelligence . Publication of that communique outraged Americans just as German U-boats started sinking American merchant ships in the North Atlantic . Wilson then asked Congress for "a war to end all wars" that would "make the world safe for democracy", and Congress voted to declare war on Germany on April 6, 1917 . On December 7, 1917, the U.S. declared war on Austria - Hungary . U.S. troops began arriving on the Western Front in large numbers in 1918 . </P> <P> After the war began in 1914, the United States proclaimed a policy of neutrality despite president Woodrow Wilson's antipathies against Germany . Early in the war, the United States started to favor the British and their allies . President Wilson aimed to broker a peace and sent his top aide, Colonel House, on repeated missions to the two sides, but each remained so confident of victory that they ignored peace proposals . </P> <P> When the German U-boat U-20 sank the British liner Lusitania on 7 May 1915 with 128 US citizens aboard, Wilson demanded an end to German attacks on passenger ships, and warned that the US would not tolerate unrestricted submarine warfare in violation of international law and of human rights . Wilson's Secretary of State, William Jennings Bryan, resigned, believing that the President's protests against the German use of U-boat attacks conflicted with America's official commitment to neutrality . On the other hand, Wilson came under pressure from war hawks led by former president Theodore Roosevelt, who denounced German acts as "piracy", and from British delegations under Cecil Spring Rice and Sir Edward Grey . </P>

Who did the united states fight in ww1