Total war, by definition, is war fought by any and all means available.
The subject of total war was first treated theoretically by the Prussian military theorist Karl von Clausewitz, who used the term absolute war and pointed out that the stronger the motivation for war is, the more the resulting war will approach totality.
However, von Clausewitz denied the likelihood of truly total war ever occurring; any war approaching totality would be modified by the fact that war is not an isolated act, and does not consist of a single battle, where all strength can be committed at a particular instant and a specific location. Because of the possibility of retaliation, von Clausewitz argued, reserves will always exist, and war will never achieve true totality.
Total war, as a propaganda concept, recurs in the Nazi rhetoric during World War II. That war, however, was never close to total, because both sides refrained from using all means available (e.g., mustard gas, so loathed after the experiences of World War I that neither side wanted to be the first to use it).
Similarly, the prevalence of nuclear weapons makes total war unlikely, because the extreme destructiveness of the weapons, and their global impact, ensure that their use is tantamount to suicide - national if not racial.