How can you argue that imperialism was more important than alliances and militarism as the underlying cause of world war i?

At the end of World War I, President Wilson offended members of the United States Senate by travelling to Europe and opposing the League of Nations as well as opposing the views of Henry Cabot Lodge, thereby excluding them from the peace process.  President Wilson was the President of the United States during the first world war. He tried to keep the USA out of the war but ultimately had to join the Allies against Germany in 1917.  He also help broker a peace treaty with the USA joining the League of Nations. The US Congress vetoed this idea.