The aim of this paper is to discuss if after and as a consequence of the attack to the Twin Towers and the «war on terrorism» promulgated by Bush, Jr. – the notion of war has been altered. In order to respond to this question, the Clausewitzian definition of war is re-discussed in the light of the fundamental difference between war and politics. It is almost always maintained that the two have the same logical status and that they recall each other. Here is argued that in reality whereas politics determine war, the reverse is impossibile. The most important classical literature on the topic, from Aristotle to Hobbes, Hegel, and the most well known contemporary scholars, is revisited. The most startling thinker is E. Luttwak, who considers that war must be let free to unchain all the violence it intrinsically possesses in order «to give the war a chance», as he himself says. Many minor wars are unable —according to Luttwak— to exhaust the violence intrinsic in the crises around the world. Wars always end, he thinks, only if/when winner has been able to destroy completely the adversary. But this would realize the Clausewitzian absolute war. Notwithstanding, also if many continue to think that the recently varied «underwars» that have appeared (private military forces, battles zero-deads, drones, et cetera) may produce a change in the nature of war, a correct reading of the Clausewitzian thought demonstrates that this is impossible because what may change is not war but politics. War is not the opposite of politics, but a consequence of it, to the rules of which war is obliged to obey. This means that the most important task for our times is not so much reduce the occurrences of war but to introduce in politics a growing rate of democracy, which is, by nature, non-violent.