Technically Germany declared war on the US, not the other way around.
As for war with Britain (and France), they had formally committed to it in the event that Germany invaded Poland. In retrospect it was odd that Hitler seriously thought they might not attack him; it looks more like hope than rational expectation.
Technically Germany declared war on the US, not the other way around.
As for war with Britain (and France), they had formally committed to it in the event that Germany invaded Poland. In retrospect it was odd that Hitler seriously thought they might not attack him; it looks more like hope than rational expectation.
Human precommitment is pretty weak, and national precommitment more so (cf Budapest Memorandum elsewhere in the thread).