I've seen threads that asked how a D-Day failure would impact the outcome of the war. This thread is more concerned with what the impact would be at home in the US?
From what I can tell, the US military was more accountable to public opinion than most others. If D-Day was ultimately a failure, with many men killed or captured, I imagine that there would have been calls to sack Eisenhower at the very least. What about Marshall, who mostly organized the whole thing? Let's not forget that Roosevelt is up for reelection, so a major defeat would have a huge impact on his campaign. Would it be enough to get Dewey elected?
Finally, what would public enthusiasm be like at home? Many young men (and their parents) would suddenly become disenchanted with joining the military now that it won't be as simple as hopping the pond and kicking some Nazi ass. Any thoughts?