Carl von Clausewitz and the Clausewitzian Viewpoint of Warfare: A Theoretical Approach

By Dr. Vladislav B. Sotirovic, Ex-University Professor, Research Fellow at Centre for Geostrategic StudiesBelgrade, Serbia

The Focal Questions About Wwar

In dealing with both theoretical and practical points of view about war, at least six fundamental questions arise:

1) What is war?
2) What types of war exist?
3) Why do wars occur?
4) What is the connection between war and justice?
5) The question of war crimes?
6) Is it possible to replace war with the so-called “perpetual peace”?

Probably, up to today, the most used and reliable understanding of war is its short but powerful definition by Carl von Clausewitz:

War is merely the continuation of politics by other means. [On War, 1832].

It can be considered the terrifying consequences if, in practice, Clausewitz’s term “merely” from a simple phrase about the war would be applied in the post-WWII nuclear era and the Cold War (for instance, the Cuban Missile Crisis in 1962).

Nevertheless, Clausewitz became one of the most important influencers on Realism in international relations (IR). To remind ourselves, Realism in political science is a theory of IR that accepts war as a very normal and natural part of the relationships between states (and after WWII, of other political actors as well) in global politics.

Realists are keen to stress that wars and all other kinds of military conflicts are not just natural (meaning normal) but even inevitable. Therefore, all theories that do not accept the inevitability of war and military conflicts (for instance, Feminism) are, in fact, unrealistic.

The Art of War Is an Extension of Politics

A Prussian general and military theorist, Carl Philipp Gottfried von Clausewitz (1780−1831), the son of a Lutheran Pastor, entered the Prussian military service when he was only 12, and achieved the rank of Major-General at 38. He was studying the philosophy of Immanuel Kant and became involved in the successful reform of the Prussian army.

Clausewitz was of the opinion that war is a political instrument similar to, for instance, diplomacy or foreign aid. For this reason, he is considered to be a traditional (old-school) realist.

Clausewitz echoed the Greek Thucydides, who had described in the 5^th century B.C. in his famous The History of the Peloponnesian War the dreadful consequences of unlimited war in ancient Greece. Thucydides (ca. 460−406 B.C.) was a Greek historian but had a great interest in philosophy too. His great historiographical work, The History of the Peloponnesian War (431−404 B.C.), recounts the struggle between Athens and Sparta for geopolitical, military, and economic control (hegemony) over the Hellenic world. The war culminated at the end with the destruction of Athens, the birthplace of both ancient democracy and imperialistic/hegemonic ambitions.

Thucydides explained the war in which he participated as the Athenian “strategos” (general) in terms of the dynamics of power politics between Sparta and Athens and the relative power of the rival city-states (polis). He consequently developed the first sustained realistic explanation of international relations and conflicts and formed the earliest theory of IR.

In his famous Melian dialogue, Thucydides showed how power politics is indifferent to moral argument. This is a dialogue between the Melians and the Athenians, which Thucydides quoted in his The History of the Peloponnesian War, in which the Athenians refused to accept the Melians’ wish to remain neutral in the war with Sparta and Spartan allies. The Athenians finally besieged the Melians and massacred them. His work and dark view of human nature influenced Thomas Hobbes.

Actually, Clausewitz feared that unless politicians controlled war, it would degenerate into a struggle with no clear other objectives except one – to destroy the enemy. He served in the Prussian army during the Napoleonic Wars until his capture in 1806. Later, he helped reorganize it and served in the Russian army from 1812 to 1814. He finally fought at the decisive Battle of Waterloo on June 18^th, 1815, which brought about Napoléon’s ultimate downfall from power.

The Napoleonic Wars influenced Clausewitz to caution that war is being transformed into a struggle among whole nations and peoples without limits and restrictions, but without clear political aims and/or objectives. In his On War (in three volumes, published after his death), he explained the relationship between war and politics. In other words, war without politics is just killing, but this killing with politics has some meaning.

Clausewitz’s assumption about the phenomenon of warfare was  that war has its origin in a political object, then, naturally, it means that this original motive  should also continue to be the first and highest consideration in its conduct. Consequently, the policy is interwoven with the whole action of war and must exercise a continuous influence upon it. It is clearly seen that war is not merely a political act, but as well  a real political instrument, a continuation of political commerce, a carrying out of the same by other means. In other words, the political view is the object while war is the means, and the means must always include the object in our conception.

Another important observation by Clausewitz was that the rising power of nationalism in Europe and the use of large conscript armies (in fact, national armies) could produce in the future absolute or total wars (like WWI, WWII), that is, wars to the death and total destruction rather than wars waged for some more or less precise and limited political objectives. However, he was particularly fearful of leaving warfare to the generals. Their idea of victory in war is framed only within the parameters of the destruction of enemy armies. Such an assumption of victory is contradicts the war aim of politicians, who understand victory in war as the realization of the political aims for which they started the particular war.

Nevertheless, such ends in practice could range from very limited to large, and according to Clausewitz: “… wars have to be fought at the level necessary to achieve them”. If the aim of the military action is an equivalent for the political objective, that action will, in general, diminish as the political objective diminishes”. This explains why “there may be wars of all degrees of importance and energy, from a war of extermination down to the mere use of an army of observation” [On War, 1832].

Generals and the War

Strange enough, Clausewitz: was of the strong opinion that generals should not be allowed to make any decision concerning the question of when to start and end wars or how to fight them, because they would use all instruments at their disposal to destroy an enemy’s capacity to fight. The  reason, for his concern was the possibility of converting a limited conflict into an unlimited and, therefore, unpredictable war.

This outcome occurred during WWI. The importance of massive mobilization and striking first was a crucial part of the war plans by the top military commanders. It simply meant that there was not enough time  to negotiate in order to prevent war from breaking out and  be transformed into unlimited war with unpredictable consequences.

In practice, such military-driven  strategy effectively shifted the decision about whether and when to go to war from political leadership to  the commanders  as political leaders had, in fact, little time to take all matters into consideration. They were pressed by the military leadership to quickly go to war or to accept responsibility for the defeat. From this viewpoint, military plans and war strategies completely reversedthe relationship between war and politics and between civil politicians and military generals that Carl von Clausewitz had advocated a century earlier.

It has to be recognized, nonetheless, that Prussian General Carl von Clausewitz, in fact, predicted the first total war in history in which generals dictated to political leaders the timing of military mobilization and pressed politicians to take both the offensive and strike first. The insistence, in effect, of some of the top military commanders on adhering to pre-existing war plans, as it was, for instance, the case with Germany’s Schlieffen Plan and mobilization schedules, took decision-making out of the hands of politicians, i.e., civilian leaders. Therefore, in such a way, it circumscribed the time those leaders had to negotiate with one another to prevent  bloodshed. Furthermore, the military leaders also pressured civilian leaders to uphold alliance commitments and consequently spread a possibly limited war across Europe into a European total war.

As a matter of illustration, the best-known  is Germany’s Schlieffen Plan, as it was named after German Count Alfred von Schlieffen (1833−1913), who was the Chief of the German Great General Staff from 1891−1905. The plan was revised several times before WWI started. The Schlieffen Plan, like some other war plans created before WWI by the European Great Powers, was founded on the assumption of the offensive as essential  to success. The key to the offensive, however, was a massive and very quick military mobilization, i.e., quicker than the enemy could do the same. Something similar was designed during the Cold War when the primacy of a nuclear first strike was at the top of military plans’ priority by both superpowers.

Nevertheless, a massive and even general military mobilization meant gathering troops from the whole country at certain mobilization centers to receive arms and other war materials, followed by the transportation of them together with logistic support to the frontlines to fight the enemy. So in order to win the war, a belligerent had to invest huge expenses and significant time to be able to strike the enemy first, i.e., before the enemy could start its own military offensive.

In the run up to the Great War, the German top military leaders understood massive mobilization was crucial because  their war plans anticipated fighting on two fronts – French and Russian: they thought that the single option to win the war was by striking rapidly in the West front to win France and then decisively launching an offensive against Russia. Russia came second as  the least advanced country of the European Great Powers and Germany believed Russia would take the longest  to mobilize and prepare for war.

A Trinitarian Theory of Warfare

For Clausewitz, war has to be a political act with the intention to compel the opponent to fulfill the will of the opposite side. He further argued that the use of force has to be only a tool or a real political instrument, as, for instance, diplomacy, in the arsenal of the politicians. War has to be just a continuation of politics by other means or instruments of forceful negotiations (bargaining), but not an end in itself. Since the war has to be only initiated for the sake of achieving strictly the political goals of civilian leadership, it is logical for him that:

… if the original reasons were forgotten, means and ends would become confused [On War, 1832] (something similar, for instance, occurred with the American military intervention in Afghanistan from 2001 to 2021).

He believed that when  original reasons for war are forgotten,  the use of violence will be irrational.  To be usable, war has to be limited.

However,  developments of the last several hundred years like industrialization or enlarged warfare, have taken warfare in direction that had alarmed Clausewitz. In fact, he warned that militarism can be extremely dangerous for humanity – a cultural and ideological phenomenon in which military priorities, ideas, or values are pervading the larger or total society (for instance, Nazi Germany).

The Realists, actually, accepted Clausewitz’s approach, which later after WWII, was further developed by them into a view of the world that is distorted and dangerous, causing the so-called “unnecessary wars”. In general, such kinds of wars have been attributed to the US foreign policy during and after the Cold War around the globe. For example, in South-East Asia during the 1960s the US authorities were determined not to appease the Communist powers that they likened to the German Nazis of  the 1930s. Consequently,  to avoid a Communist occupation of Vietnam, the US became involved in a pointless and, in fact, unwinnable war,  confusing Nazi aims of geopolitical expansionism with the legitimate post-colonial patriotism of the people of Vietnam.

Carl von Clausewitz is by many experts considered to be the greatest writer on military theory and war. His book On War (1832) is generally interpreted as favoring the very idea that war is, in essence, a political phenomenon as an instrument of policy. The book, nevertheless, sets out a trinitarian theory of warfare that involves three subjects:

1. The masses are motivated by a sense of national animosity (national chauvinism).
2. The regular army devises strategies to take account of the contingencies of war.
3. The political leaders formulate the goals and objectives of military action.

Critics of the Clausewitzian Viewpoint of War

However, from another side, the Clausewitzian viewpoint of war can be deeply criticized for several reasons:

1. One of them is the moral side of it, as Clausewitz was presenting war as a natural and even inevitable phenomenon. He can be condemned for the justification of war by reference to narrow state interest instead of some wider principles, like justice or so. However, such his approach, therefore, suggests that if war serves legitimate political purposes, its moral implications can be simply ignored, or in other words, not taken at all into account as an unnecessary moment of the war.
2. Clausewitz can be criticized for the reason that his conception of warfare is outdated and therefore not fitting to modern times. In other words, his conception of war is relevant to the era of the Napoleonic Wars, but surely not to modern types of war and warfare for several reasons. First, modern economic, social, cultural, and geopolitical circumstances may, in many cases, dictate that war is a less effective power than it was at the time of Clausewitz. Therefore, war today  is an obsolete policy instrument. If contemporary states are rationally thinking about war, military power can be of lesser relevance in IR.  Second, industrialized warfare, and especially the feature of total war, can make calculations about the likely costs and benefits of war much less reliable. If it is the case, then war can simply stop being an appropriate means of achieving political ends. Thirdly, most of the criticism of Clausewitz stresses the fact that the nature of both war and IR has changed and, therefore, his understanding of war as a social phenomenon is no longer applicable. In other words, Clausewitz’s doctrine of war can be applicable to the so-called “Old wars“ but not to the new type of war – “New war“. Nevertheless, on the other hand, in the case that Clausewitz’s requirement that the recourse to war has to be based on rational analysis and careful calculation, many modern and contemporary wars would not have taken place.

© Vladislav B. Sotirovic 2025