Germany's apparently rapid collapse in the autumn of 1918 was the result of both its ill-judged offensive of the previous March, and a series of allied offensives in the summer in which the tactical lessons, learned in the previous four years, were finally used to good effect. On 4 October President Wilson was formally asked by the German High Command to bring about a cease-fire on the basis of his ‘fourteen points’. Within five weeks, the Kaiser had abdicated and the armistice had been signed. by May 1919 the allies had agreed between themselves at Versailles a harsh peace treaty, which nevertheless included the establishment of a League of Nations. This treaty was presented as a fait accompli to the central powers for their agreement. On 28 June 1919 it was signed by Germany.

The nature of the political debate on foreign affairs had dramatically changed: rather than proposals, ideals and speculations, it was the post-war settlement as it had actually been agreed and the structure of the League of Nations as it existed that now provided the framework for discussion. The main questions for progressives became the extent to which the fundamentals of the post-war settlement could be accepted. To what extent could any necessary changes be made by incremental reform? In answering these questions, the responses of individuals and organisations were bound to be influenced by the way in which they had interpreted the events of the previous four years.