When war broke out in Europe in 1914 the US proclaimed a state of neutrality. Economically the US started to favor the British and their Allies. Tensions would rise between US and Germany when the Germans started using submarines to sink commercial vessels sailing under a neutral flag, in hopes of cutting off the British supply lines. President Woodrow Wilson tried to broker peace between Germany and the Entente, a peace that was not to be. When Germany resumed its policy of unrestricted submarine warfare America entered the war.