sloreck:
What would those effects be? The intuitive answer would be stronger peace movements, greater isolationism and greater difficulty getting into a second war if there is one. But perhaps counter-intuitively the US would be more determined to keep the Germans down/contained. US losses were much greater in WWII, but the US held its international position. The USSR in the face of massive WWII losses did not go isolationist, rather it was determined to hold down a buffer zone for 44 years.
Having a large AEF in the trenches about 18 months earlier will mean much larger US casualties, no matter what sort of tactics are used. Needless to say this will have huge effects afterwards in terms of peace movements and isolationism.
What would those effects be? The intuitive answer would be stronger peace movements, greater isolationism and greater difficulty getting into a second war if there is one. But perhaps counter-intuitively the US would be more determined to keep the Germans down/contained. US losses were much greater in WWII, but the US held its international position. The USSR in the face of massive WWII losses did not go isolationist, rather it was determined to hold down a buffer zone for 44 years.