"Total war" as a term can be applied quite loosely. As to whether it is a reliable description of a conflict, that ultimately depends on which conflict you are referring to. The Second World War, for instance, is often spoken about as the closest a conflict has come to being "total war", essentially because it fulfills to a great extent the two main requirements. Both alliances in the Second World War devoted huge proportions of their economies to the war effort, in some cases gearing their entire economies to war industries. Similarly, both alliances frequently attacked targets that are traditionally seen as protected by the laws of war, such as by pursuing unrestricted submarine warfare or by indiscriminate bombing of cities. "Total war" isn't generally dependent upon the particular political motivations for the war, but the extent to which the economy is dedicated to the war is important.