I know that "wage war" is an idiomatic expression that the American Heritage Dictionary defines as:
To engage in (a war or campaign, for example).
and Dictionary.com defines as:
to carry on (a battle, war, conflict, argument, etc.): to wage war against a nation.
My question is: does "wage war" mean also 'declare war" or does it refer only to the development of war operations? (Sorry but I have this doubt).