[dragonwriter]

No, used literally "war" (without modifiers like "civil", etc.) refers to a thing waged between countries. War on concepts are a metaphor, not a literal description, that puts the—actual or for-propaganda-purposes—goal of a set of policies front and center rather than actual policies ((which may or may not be or include literal wars on countries; consider the range from the "War on Poverty" through the "War on Drugs" to the "Global War on Terror".)

[wmf]

I don't disagree with any of that but I don't think it's relevant to the on vs. in hair-splitting either.