This is a general discussion room, but please feel free to create more subject-specific rooms (a single room with every possible discussion isn't very helpful)
@HarleyHolcombe interesting question. When it comes to Nazi Germany, with Hitler being the dictator, he was directly responsible for most of the political (especially war) decisions. He was the one that was speaking for the whole nation, so I think, the wording "Hitler declared war" is appropiate (and widely used). But after all is it about a whole nation going to war after that...
@Jacob I know philosophically the question could be asked on the main site, I'm mainly wondering for wording in general. See also history.stackexchange.com/questions/71/…