On War

Clausewitz argued that war theory cannot be a strict operational advice for generals.[5] Instead, he wanted to highlight general principles that would result from the study of history and logical thinking. He contended that military campaigns could be planned only to a very small degree because incalculable influences or events, so-called friction, would quickly make any too-detailed planning in advance obsolete. Military leaders must be capable to make decisions under time pressure with incomplete information since in his opinion "three quarters of the things on which action is built in war" are concealed and distorted by the fog of war.[6]

In his 1812 Bekenntnisschrift ("Notes of Confession"), he presents a more existential interpretation of war by envisioning war as the highest form of self-assertion by a people. That corresponded in every respect with the spirit of the time when the French Revolution and the conflicts that arose from it had caused the evolution of conscript armies and guerrillas. The people's armies supported the idea that war is an existential struggle.[7][8]

During the following years, however, Clausewitz gradually abandoned this exalted view and concluded that the war served as a mere instrument: "Thus, war is an act of violence in order to force our will upon the enemy."[9]

Clausewitz analyzed the conflicts of his time along the line of the categories Purpose, Goal and Means. He reasoned that the Purpose of war is one's will to be enforced, which is determined by politics. The Goal of the conflict is therefore to defeat the opponent in order to exact the Purpose. The Goal is pursued with the help of a strategy, that might be brought about by various Means such as by the defeat or the elimination of opposing armed forces or by non-military Means (such as propaganda, economic sanctions and political isolation). Thus, any resource of the human body and mind and all the moral and physical powers of a state might serve as Means to achieve the set goal.[10]

One of Clausewitz's best-known quotes summarizes that idea: "War is the continuation of policy with other means."[9]

That quote in itself allows for the interpretation that the military will take over from politics as soon as war has begun, as, for example, the German General Staff did during World War I. However, Clausewitz had postulated the primacy of politics and in this context elaborated: "[...], we claim that war is nothing more than a continuation of the political process by applying other means. By applying other means we simultaneously assert that the political process does not end with the conclusion of the war or is being transformed into something entirely different, but that it continues to exist and proceed in its essence, regardless of the means, it might make use of."[11]

According to Azar Gat, the "general message" of the book was that "the conduct of war could not be reduced to universal principles [and is] dominated by political decisions and moral forces."[12][13] These basic conclusions are essential to Clausewitz's theory:

• War must never be seen as having any purpose in itself but should be seen as a political instrument: "War is not merely a political act, but a real political instrument, a continuation of the political process, an application by other means."[14]
• The military objectives in war that support one's political objectives fall into two broad types: "war to achieve limited aims" and war to "disarm" the enemy: "to render [him] politically helpless or militarily impotent."
• All else being equal, the course of war will tend to favor the party with the stronger emotional and political motivations, especially the defender.[1]

Some of the key ideas (not necessarily original to Clausewitz or even to his mentor, Gerhard von Scharnhorst) discussed in On War include[15] (in no particular order of importance):

• the dialectical approach to military analysis
• the methods of "critical analysis"
• the uses and abuses of historical studies
• the nature of the balance-of-power mechanism
• the relationship between political objectives and military objectives in war
• the asymmetrical relationship between attack and defense
• the nature of "military genius"
• the "fascinating trinity" (Wunderliche Dreifaltigkeit) of war
• philosophical distinctions between "absolute or ideal war," and "real war"
• in "real war," the distinctive poles of a) limited war and b) war to "render the enemy helpless"
• "war" belongs fundamentally to the social realm, rather than the realms of art or science
• "strategy" belongs primarily to the realm of art
• "tactics" belongs primarily to the realm of science
• the essential unpredictability of war
• simplicity: Everything is very simple in war, but the simplest thing is difficult. These difficulties accumulate.[16] The strength of any strategy lies in its simplicity.[17]
• the "fog of war"
• "friction"
• strategic and operational "centres of gravity"
• the "culminating point of the offensive"
• the "culminating point of victory"

Clausewitz used a dialectical method to construct his argument, which led to frequent modern misinterpretation because he explores various often-opposed ideas before he came to conclusions.

Modern perceptions of war are based on the concepts that Clausewitz put forth in On War, but they have been diversely interpreted by various leaders (such as Moltke, Vladimir Lenin, Dwight Eisenhower, and Mao Zedong), thinkers, armies, and peoples. Modern military doctrine, organization, and norms are all still based on Napoleonic premises, but whether the premises are necessarily also "Clausewitzian" is debatable.[18]

The "dualism" of Clausewitz's view of war (that wars can vary a great deal between the two "poles" that he proposed, based on the political objectives of the opposing sides and the context) seems to be simple enough, but few commentators have been willing to accept that crucial variability. They insist that Clausewitz "really" argued for one end of the scale or the other. On War has been seen by some prominent critics as an argument for "total war".^[a]

It has been blamed for the level of destruction involved in the First and the Second World Wars, but it seems rather that Clausewitz, who did not actually use the term "total war", had merely foreseen the inevitable development that started with the huge, patriotically motivated armies of the Napoleonic wars. They resulted (though the evolution of war has not yet ended) in the atomic bombing of Hiroshima and Nagasaki, with all the forces and capabilities of the state devoted to destroying forces and capabilities of the enemy state (thus "total war"). Conversely, Clausewitz has also been seen as "The preeminent military and political strategist of limited war in modern times".[19]

Clausewitz and his proponents have been severely criticized by other military theorists, like Antoine-Henri Jomini[20] in the 19th century, B. H. Liddell Hart[21] in the mid-20th century, and Martin van Creveld[22] and John Keegan[23] more recently.[24] On War is a work rooted solely in the world of the nation state, states historian Martin van Creveld, who alleges that Clausewitz takes the state "almost for granted", as he rarely looks at anything before the Peace of Westphalia, and mediaeval warfare is effectively ignored in Clausewitz's theory.[22] He alleges that Clausewitz does not address any form of intra/supra-state conflict, such as rebellion and revolution, because he could not theoretically account for warfare before the existence of the state.[25]

Previous kinds of conflict were demoted to criminal activities without legitimacy and not worthy of the label "war". Van Creveld argues that "Clausewitzian war" requires the state to act in conjunction with the people and the army, the state becoming a massive engine built to exert military force against an identical opponent. He supports that statement by pointing to the conventional armies in existence throughout the 20th century. However, revolutionaries like Karl Marx and Friedrich Engels derived some inspiration from Clausewitzian ideas.[25]