I have a set of questions below, but don't feel the need to answer all of them.
Is the idea of a "war on [blank]" unique to post-WWII American society or can it be traced to earlier eras? How does this rhetoric affect policy-making, and what might it say about how Americans view war and/or domestic politics? Is there perhaps any historical significance in the fact that we rarely hear about a war for some issue, but only on or against an issue? What exactly has a "war" on a specific social problem entailed in the past (perhaps, for example, the mass mobilization of American society and political institutions)? Is this type of rhetoric unique to the United States?
Since no one has replied yet, this isn't my field but my understanding is that this rhetoric dates back to William James' 1906 essay "The Moral Equivalent of War," in which he calls for civilian progress to be made on a war footing.
He asks for a conscription of men in peacetime to "coal and iron mines, to freight trains, to fishing fleets in December, to dishwashing, clotheswashing, and windowwashing, to road-building and tunnel-making, to foundries and stoke-holes, and to the frames of skyscrapers." Although he is anti-war he believes "so far, war has been the only force that can discipline a whole community."
LBJ's war on poverty rhetoric is almost identical to the essay. Jimmy Carter made the reference explicit in his "Moral Equivalent of War Speech" in 1977.
The text of the essay, as published in 1910, is here: http://en.wikisource.org/wiki/The_Moral_Equivalent_of_War