Wilson advocated international law and arbitration. In January 1917 he had made an unsuccessful attempt to persuade the belligerents to end the war, calling for a "peace without victory". After the USA had entered the war, Wilson outlined his view on a post-war settlement through his "Fourteen points". These became the guiding principles for the Paris Peace Conference (1919-20), and included the establishment of the League of Nations. However, Wilson failed to obtain ratification of the Treaty of Versailles, and the USA did not join the League of Nations.