Woodrow Wilson WWI- What had changed in the year between January 1917 and January 1918?

In his “Peace Without Victory” speech of January 1917, Wilson had seen the war as a grubby nationalistic conflict that could be settled by a territorial compromise. One year later, in his “Fourteen Points” speech, he saw the war as a moral crusade in which righteousness belonged to only one side. What had changed in the year between January 1917 and January 1918?