Aren’t we talking here about WWI?
Many historians argue that WWII was simply a continuation of WWI.
While France wasn’t crushed by the Germans in WWI like they were in WWII, major parts of the country were under German control. In 1917 the Russian Revolution and their peace agreement with Germany meant the Germans got massive reinforcements for the Western Front. It is certainly arguable that the French would have collapsed without the stiffening of the lines the American forces allowed.