War does not need to be declared; but a national emergency does.
I'm not sure I understand what you are saying.
The original question was: AND - will someone please confirm that if we are in a state of war at the time of elections, the elections can be postponed or suspended by Presidential edict?
The question, as asked, stipulated "war". We are not in a state of war. That is indisputable. Congress has declared war on no one.
So: Are you saying that the president can postpone the election in a (your words) "national emergency"? Could you cite something to back that up, please?