Hello,
very good discussion, we should turn this into a history thread and publish it
There were certainly "contacts" between US american escorts and german U-boats, so even if it was not an official war, and some U-boat commanders demanded action against "neutral" warships giving away their position and helping to hunt them down, there were already a lot of tensions. As well US policy ahad expanded the US american territorial waters to the midst of the atlantic (against international law), and every ship sunk in "their" territory by a U-boat would have instantly led to an american declaration of war. The US were at that time indeed looking for a reason to officially support England, and would use every event to explain it to their people. That was why Germany was so reluctant in taking action against the US, even if they already supported England with their actions.
Then there was the "Momp", the mid-ocean meeting point, where US ships should hand the convoy from "their" territory into British hands, and have it escorted to England. Some of the US escorts would indeed not turn around. As well the position of this "border" was doubtful to say at least.
It is hard enough to distinguish between US and british escort ships during an attack through a periscope. The sinking of the "Reuben James" by Lt. Topp must have been the first US casualty in a war not yet declared.
Even then a declaration of war towards the US was not really a well-thought plan. Doenitz had demanded the unrestricted U-boat war from Hitler, because his U-boat crews could not be expected to distinguish between the flags of small warships in the heat of a battle, but even he accepted the "expanded" territorial waters until war was declared, and was sure what a violation would have meant.
As far as i understand Hitler hoped to divert the US, if they engaged in a two front war, to substract forces from the european theatre later. Hitler also hoped Japan would attack Russia in land battles and also draw it into a two-front war.
I remember what my father said, how most people in Germany considered the war to be lost already in 1941, but sure as soon as Hitler declared war to the US. As well Hitler's decision to take the city of Stalingrad brought the german forces to a standstill. Would have Stalingrad been circumvented and isolated by the army (like Leningrad) things might have developed differently. However the name Stalingrad was an offensive to Hitler (or so he thought), so it had to be taken at all costs.
B.t.w. the GROEFAZ thing, with "Groesster Feldherr aller Zeiten": This turned into a cynical joke in the Wehrmacht and among the people, because it had become obvious what Hitler's kind of warfare really did to the people of Germany and the other states, it indeed was making fun of the "wise and glorious Fuehrer". It was considered a taboo word, and you were indeed accused and arrested and maybe shot if you said "Groefaz" in the public - it was not a term lickspittles used.
There was another joke like
"do you know the US have thousand ships, tenthousand tanks and millions of soldiers"
and the answer:
"Golly! if only the Fuerer knew this"
This answer to be given to all kinds of statements would as well lead to an arrest, like anything else making fun about Hitler. It was a dictatorship after all.
Greetings,
Catfish