Prior to the First Battle of the Marne in September of 1914, Germany was rolling steadily along, even getting within 50 miles of Paris. It was only after the 'genius of the Marne' that Germany stopped in its tracks, the "race to the sea" and setting up stalemate over ~450 miles of front.
My question is whether success of the Schlieffen Plan and a German victory at the Marne would have drastically altered the course of events in WWI. If the war doesn't develop into grueling trench warfare, Germany might well have captured Paris before 1915.
What possible effects do you think this would have had on the British will to fight, the Eastern Front and Bolshevik Revolution, American entry into the war (and becoming a major power), the German Revolution and the Weimar Republic, Hitler and the Second World War, etc.?
I just think it's interesting to speculate how events could have turned out very, very differently but for seemingly minor details.