Five Things That Helped Carl von Clausewitz Become A Great Strategic Thinker

While Carl von Clausewitz is often quoted, in reality his treatise On War is rarely studied in depth. Aside from the book’s unfinished character, the difficulty in translating nineteenth century German into modern English, combined with interpreting complex ideas and placing them into current context, makes it easy to understand why military professionals and the general public quickly abandon reading the book. In times when the U.S. military struggles to find its strategic footing, reading and debating Clausewitz’s complex ideas are needed more now than ever before.

Perhaps even the times and conditions in which he developed them deserve a second look, for they contain lessons about how strategic thinkers grow and develop. As someone who has extensively studied Clausewitz’s life and legacy, and complex relationship with his wife Marie, I frequently mull over the question of how this penniless Prussian officer from the provinces evolved into the West’s most influential military thinker.

The French Revolution

Carl von Clausewitz was only nine years old when an angry mob stormed the Bastille in Paris. This earth-shattering event forever marked his life, career, and mind.

Bataille de Jemmapes 1792 (Wikimedia)

Then as now, war promises rapid promotion, glory, and many opportunities, yet it leaves behind pain, bitterness, and many unanswered and unanswerable questions. The French Revolution and the ensuing Napoleonic Wars advanced Clausewitz’s career, but on personal level they left an unbearable burden.

Rising through the ranks of Frederick the Great’s aristocratic army would have been difficult and slow for someone like Clausewitz, with his murky claims to nobility. Recall the path of his older friend August Neidhardt von Gneisenau, as much a self-made man as Clausewitz. In his first twenty years of service, Gneisenau rose only to captain, but then after the reforms of 1806 became general in just nine years. One generation later Clausewitz was luckier—he became a major by the age of thirty.

The Prussian defeat at the hands of Napoleon in 1806 at Jena-Auerstedt broke open the door for a whole new generation of officers. In its wake, the Military Reorganization Commission relieved 101 of 142 general officers in the Prussian army. The organization literally awoke to brand new management.   

More importantly for Clausewitz the strategic thinker, he observed closely one of the most implacable phenomena in modern history. In 1789, a political revolution occurred that elevated every Frenchman to the status of citizen who could be called upon to protect the nation. The Revolutionary army fought with remarkable élan and enjoyed almost limitless reserves. The rising tide lifted many boats, and exceptionally talented junior officers like Napoleon, Bernadotte, Murat, and Junot were given chances they might never have had in the Ancien Régime.

The French Revolution unleashed ferocity never seen before on the battlefield. It first startled the old regimes, but then they struggled to recreate these conditions as a way to defeat Napoleon. As someone belonging to the Prussian reform circle, Clausewitz remained fascinated with the relationship between war and politics until his death. He studied in detail and often revisited the topics of people in arms, escalation of violence, decisiveness and risk in battle, and military victory and political consequences.

In his pursuit, Clausewitz was not the exception. Many wrestled to understand the momentous and violent events they had experienced. Antoine-Henri Jomini, for example, may have been the most famous military writer of the era, but scores of memoirs, studies of campaigns, and treatises on military leadership and strategy were published in the early nineteenth century. Clausewitz became a prolific reader of these texts, as his correspondence bears witness.

What distinguished his work was an incredible ambition; he sought to describe the events he had witnessed in their totality while testing long-held dogmas and analyzing the phenomenon of war with a realist language. Still, an important element was lacking. He needed a mentor.   

Great Mentorship

"Scharnhorst" by Friedrich Bury (Wikimedia)

Marie von Clausewitz emphasized this point clearly. As she wrote after her beloved husband’s death in 1832, when Carl first entered the Prussian Kriegsakademie he almost failed it. “In the beginning, it was very hard for him to follow the lectures because of his lack of essential knowledge. [Clausewitz] was close to despair, and probably would have given up on the hard endeavor, if it wasn’t for [Gerhard von] Scharnhorst, who encouraged him with his unique kindness and benevolence,” Marie wrote. [1]

Similar to his talented pupil, Scharnhorst was also an outsider and a self-made man. The son of a Hanover farmer, Scharnhorst lacked noble birth, and for a decade he was confined to the rank of lieutenant. Supplementing his income with writing, Scharnhorst’s texts on military theory and practice ultimately brought him prestige and attention. In 1801, Scharnhorst accepted an offer from Prussian king Friedrich Wilhelm III to transfer to Berlin. There, he became the head of the Academy for Young Officers of the Infantry and Cavalry, later renamed the Prussian Military Academy (Kriegsakademie). The selection of students there was based on merit, and Clausewitz enrolled in its first class.

Yet Scharnhorst had plans for nothing less than the complete overhaul of the Prussian army. Simultaneously, he created in Berlin the Military Society (Militärische Gesellschaft), a group where civilians, officers of all ranks, reformers, and reactionaries were all welcome...provided they had something to contribute to the ongoing debates. Just as at the Kriegsakademie, the goal was not to preach what to think. Instead, Scharnhorst recognized the complexities of warfare and taught individuals how to think about strategic dilemmas. From the Military Society many of the ideas and personalities would emerge that later transformed the Prussian army and ultimately led it to its victory over the era’s greatest military leader, Napoleon.

"Reorganisation," a painting by Carl Röchling depicting the Militärische Gesellschaft at Königsberg in 1807. (Wikimedia)

Scharnhorst won immortal glory on the battlefield and died in 1813. Yet the years as a passionate director of the Kriegsakademie, head of the military reform committee, and chief of the Prussian General Staff were his true and lasting legacy.

His long, bitter decade as lieutenant taught Scharnhorst empathy and wisdom. He understood that talent needed to be actively sought, nurtured, and promoted, especially when it came in a rough shape, as in the case of Clausewitz. Scharnhorst recognized that reforms required a strong network of people prepared to implement them, when the time was right.      

The relationship between Scharnhorst and Clausewitz underlines the pivotal role a mentor can play in discovering and developing talents. Building a network—either as mentor or mentee, getting to know the people with whom we work and supporting their aspirations, building a community and a bridge between junior and senior ranks—is a process that yields long-lasting benefits, for everyone.             

A Partner

In our own time, time Sheryl Sandberg is a technology executive and best-selling author who argues the most important decision one makes about his or her career is whom to marry. Two hundred years ago, Clausewitz recognized something similar, that no one succeeds in this life alone. In his correspondence he described Marie and their partnership as his life’s greatest fortune.

There were two things that made him feel proud of himself, Clausewitz wrote in 1807 as a twenty-six-year-old subaltern captain (something like a promotable lieutenant). The first one was commanding troops in the Battle of Jena-Auerstedt and the second winning Marie’s love. The latter, he admitted sincerely, brought him close to the life he dreamed of:

I had this need to love—and which sensible individual does not know this beautiful desire—but love which would have pulled me back into life’s trivial routine would have made me bitter and unhappy; yet falling in love with such an extraordinary person, this has brought me one step closer to the noble path.[2]          

Clausewitz’s marriage to Marie, born Countess von Brühl, was marked by a deep and passionate love. Nevertheless, biographers contemplated how an obscure lieutenant could have even dreamed of courting an imperial count’s daughter, who herself was an intimate of the royal family. Peter Paret suggests the young officer’s pursuit of the clearly socially superior Marie underscores his audacity, boundless ambition, and strong character.[3]  

Marie von Clausewitz (Wikimedia)

As a political woman and a well-connected courtier, she was of enormous importance in supporting Clausewitz’s career. Marie also provided him with invaluable insight about how politics and decisions were made at the highest level, an elusive realm even for early nineteenth century military men. She also exposed him to diverse ideas and flamboyant characters. In the beginning of their relationship, the young officer snarled at Berlin’s gaudy literati, but he gradually learned to appreciate the intellectual stimuli.[4]

Finding the ideal partner in life is a matter of luck. Yet actively searching for ideas, literary works, and people who will challenge our minds and enrich our life is a crucial trait for strategic leaders.    

Marie was fully integrated in Clausewitz’s work, as her handwriting in his remaining manuscripts reveals. Clausewitz joked once that she was his “staff officer.”[5] Marie was the debate partner he need to hone his ideas, the meticulous researcher when he lacked time and access to a library, the secretary writing down the ideas he dictated, the one who kept his manuscripts safe, and above all a believer in his life’s work. In all probability, Clausewitz, despite being gravely ill in his later life, never felt the urge to publish On War prematurely, for he knew that in a case of sudden death Marie would take care of his legacy.               

Without Marie’s dedication and commitment, On War would have never become the classic work we know and rely upon today. When Clausewitz died in 1831, she sought to publish the manuscripts just as they were, “without one word being added or deleted.”[6] This meant publication without intense rewritings or any corrections to consolidate the text and make it an easier read, keeping is as close as possible to Clausewitz’s last changes.

Modern readers might wish Marie had been a more hands-on editor. Yet consider what happened when her younger brother Fritz von Brühl prepared the second edition of On War in 1850s. He rightfully fixed grammatical and print errors and modernized the language, but he then went a step further, altering the meaning of whole paragraphs. Consider, for example, his reversal of the relationship between policy and the military. In Book VIII, Clausewitz emphasized that the political leadership, “the cabinet,” should be involved in the major aspects of conduct of war, Brühl’s revised text suggested the complete opposite: the military commander should be part of the cabinet, as to influence political decisions. Perhaps Brühl thought his beloved brother-in-law had made a mistake needing correction. Perhaps he wished to accommodate the Prusso-German general staff’s growing desire for independence from the political realm.[7] Either way, the case illustrates the dangers of proactive and interventionist editing.

Marie anticipated that her minimalist approach opened the text to multiple and conflicting interpretations. Still, she defended it as way to uphold Clausewitz’s postulate that war theory should be descriptive and not prescriptive. By grappling with On War’s unfinished character, readers would develop clearer understanding of the complex phenomenon, wrestling with the work just as Clausewitz himself had.               

Enormous Experience

Clausewitz is often painted as an enigmatic philosopher who worked in the secluded company of his wife Marie, an officer “unpromoted and largely unhonored in his own country” for whom writing was a salvation from his bleak reality.[8]

Nothing is further from the truth. In fact, Clausewitz’s contemporaries valued him as a talented and energetic staff officer, a man who was exceptionally good at getting things done. His enormous body of work, of which On War is only the most famous and important element, was not a substitute for a failed military career but an attempt to summarize lessons synthesized from an incredibly rich professional experience.    

Shortly before his twelfth birthday he enlisted in the Prussian army as a Fahnenjunker, or a junior non-commissioned officer. As was the practice in the old Frederician army, boys who would later became officers were required to spend the early years of their service among the troops. This fostered the art of soldiery from the ground up. In his own words, Clausewitz grew up as “a son of the camp.”[9] And soon after his enlistment, Clausewitz participated in the War of the First Coalition, between 1792-1795.

This experience as a participant in great events at relatively early age continued into 1806 with the Battle of Jena-Auerstedt, the worst disaster the Prussian army would suffer at the hands of Napoleon. On that dark day, when many Prussian officers ran from the battlefield or surrendered, Clausewitz fought with honor. In 1809, at the age of twenty-eight, he became a personal assistant to Scharnhorst, now chief of the general staff and head of the war ministry. Tasked with the Herculean job of rebuilding the Prussian army, Scharnhorst relied on and trusted Clausewitz to the extent that the latter drafted and sent memoranda in the general’s name. The issues he worked on as a captain and later as a major varied from the development and manufacture of weapons, through tactical regulations, to the introduction of conscription.

His accumulation of unique experience would continue. In 1812, when Friedrich Wilhelm III was forced as a reluctant ally to provide Napoleon with troops for the Russian campaign, Clausewitz famously left Prussian service and fought on the side of the tsar. He participated in such iconic engagements as the Battles of Vitebsk, Smolensk, Borodino, and was present when Moscow was abandoned and burned.

"Panorama of Moscow Battle in 1812" (or "Battle of Borodino") by Franz Roubaud (Wikimedia)

Clausewitz continually impressed his superiors with his ability as a staff officer. In 1813, he assumed the position as chief of staff for the Russo-German Legion, but upon arriving at the headquarters General Ludwig von Wallmoden-Gimborn promptly promoted him to the chief of staff for his whole army corps, some 22,600 men. Lacking sufficient resources, Clausewitz still prepared the new formation for the fall campaign against Napoleon. Then, in 1815, he served as chief of staff for the III Prussian Corps, the unit that engaged Grouchy’s corps, twice its size, while the rest of the Prussian army rushed to support Wellington at Waterloo.

It was Clausewitz’s stroke of bad luck to be too junior when the great Napoleonic campaigns occurred, and he could not assume command as it was his heart’s desire. As an ambitious and insistent subordinate—and often grumbling outsider—he devoted much of his time and energy to understanding his surroundings, advocating for proactive leadership, and pondering the great strategic questions. Even in less-than-ideal jobs, Clausewitz found learning opportunities and never stopped writing, reading, and debating as a way to maximize his experience.

It is possible Clausewitz’s lack of high command was a blessing for posterity. Perhaps this is one of the most extensible lessons from his life, for leading an army in war is every warrior’s dream but few are the lucky ones. In the end, making the best of life might be the more realistic and advantageous goal.         

Plenty of Time for Ideas to Mature

Following the final defeat of Napoleon, Clausewitz embarked upon creating his treatise On War. It was a messy and perpetual endeavor of writing and rewriting that continued until his sudden death in November 1831.

"Carl von Clausewitz" by Wilhelm Wach (Wikimedia)

In our fast-paced era of social media, fifteen years seem an eternity. As a matter of fact, we might have to consider On War as the product of an even longer dedicated effort, for already in 1809 Clausewitz contemplated the composition of a treatise overhauling the existing military theory. In 1990 Werner Hahlweg published drafts written between 1809 and 1812. The often cited essay “On the State of Military Theory” is indeed the first chapter of this early work. [10]

These pre-On War explorations are, of course, a long way from the sophistication and maturity of his standard canon. Nonetheless, they suggest the treatise was not the product of a continuous and straightforward writing. The text of On War we know today is the result of multiple drafts, built-upon ideas, and almost endless revision. The best metaphor might be to imagine On War’s creation as a spiral movement. It started as a broader curve but continuously swirled and revisited old points, tightening and fine-tuning them, until it reached its apex.

In his later life, Clausewitz had a lot of time on his hands. From 1818 to 1830 he served as the director of Kriegsakademie in Berlin, by that point a largely administrative position and far from Scharnhorst’s all-absorbing tenure. Clausewitz’s duties required only a fraction of his day, thus allowing him time to focus on his work. He had the luxury of writing and rewriting his treatise, chasing ideas anywhere they led him and analyzing less known but interesting campaigns.

The downside of this approach is that, as Hew Strachan writes in jest, “If Clausewitz had been vouchsafed eternal life, the book would still not be finished.”[11] Yet this complexity, the elaborate arguments and refined ideas, are what make On War a great work able to endure centuries and groundbreaking changes in technology and warfare.

The broader point to make here is that ideas need time and space to mature and flourish. Certainly, no one argues modern thinkers should forsake today’s pressing matters. And Clausewitz didn’t do so, either. In addition to On War, Clausewitz frequently wrote texts concerning contemporary issues. Still we should be very wary of the constant pressure to deliver, here and now. For even the most energetic, ambitious, experienced, and bright thinker cannot infinitely bend the curve of time or deliver timeless analysis in a few constrained hours.

Final Thoughts

Historical analogies have their limits and not all past circumstances reveal eternal lessons or are pertinent to our modern conditions. We cannot recreate the French Revolution, nor should we hope for another dramatic and bloody political upheaval to sweep away the old order and give way to bright minds and untapped potential.

...even if we can't rely on a genius to emerge, if we can understand the factors that contributed to genius in another age then perhaps we can make the emergence of a great strategic thinker more likely.

Nonetheless, it is fruitful to spend time contemplating the roles mentors, networks, and exposure to diverse situations contribute to developing ideas and leaders. Stints in jobs and experiences outside narrow career paths may be crucial. Rough talent must be recognized, encouraged, and developed by leaders. Acknowledging the abiding truth that none succeed alone and balancing work and life are both necessary.  Leaders must recognize and provide the space, time, and care required for great ideas to grow.

There may never be another Carl von Clausewitz. The emergence of genius is a complex, uncertain, and contingent process which is almost impossible to control. In every age, however, the need for thinkers and strategists never abates. And even if we can't rely on a genius to emerge, if we can understand the factors that contributed to genius in another age then perhaps we can make the emergence of a great strategic thinker more likely. At the very least, we can find ways to create and nurture ability in all of us.

Vanya Eftimova Bellinger is the author of Marie von Clausewitz: The Woman behind the Making of On War and the winner of the 2016 Society for Military Moncado Prize for her article “The Other Clausewitz: Findings from the Newly Discovered Correspondence between Marie and Carl von Clausewitz.” She currently teaches at the U.S. Army War College. The views expressed are the author’s and do not reflect the position of the U.S. Army, the Department of Defense, or the U.S. Government.

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Header Image: Carl von Clausewitz, lithograph by Franz Michelis (


[1] Anonymous (Marie von Clausewitz), “Erinnerung an den General Clausewitz und sein Verhältnis zu Scharnhorst,” Historisch-Politische Zeitschrift 1 (1832): 220-223; Vanya Eftimova Bellinger, Marie von Clausewitz: The Woman Behind the Making of On War (New York: Oxford University Press, 2015), 43.  

[2] Carl to Marie, 9 April 1807. Carl and Marie von Clausewitz, Ein Lebensbild in Briefen und Tagebuchbätter, edited by Karl Linnebach (Berlin: Wegweiser-Verlag, 1916), 111.  

[3] Peter Paret, Clausewitz and The State: The Man, His Theories, and His Time (Princeton: Princeton University Press, 1985 ), 109.

[4] Carl to Marie, 3 October 1807. Carl and Marie von Clausewitz, Lebensbild, 139; Bellinger, Marie von Clausewitz, 112.  

[5] Carl to Marie, 9 June 1831. Carl and Marie von Clausewitz, Lebensbild, 463.

[6] Marie von Clausewitz, “Preface” in Carl von Clausewitz, On War, ed. and trans. by Michael Howard and Peter Paret (Princeton: Princeton University Press, 1976), 65.   

[7] Werner Hahlweg, “Das Clausewitzbild einst und jetzt,” in Carl von Clausewitz, Hinterlassene Werke. Vom Kriege. Neunzehnte Auflage (Bonn: Dümmler Verlag, 1980), 64-73 and 168-72; Hew Strachan, Clausewitz’s On War: A Biography (New York: Atlantic Monthly Press, 2007), 69-70; Bellinger, Marie von Clausewitz, 225-226.

[8] John Keegan, A History of Warfare (New York, Knopf, 1993), 20.

[9] Carl to Marie, 28 January 1807. Carl and Marie von Clausewitz, Lebensbild, 83.

[10] Carl von Clausewitz, Schriften-Aufsätze-Studien-Briefe, ed. by Werner Hahweg, Vol.2-1 (Göttingen: Vandenhoeck & Ruprecht, 1990), 23-44.

[11] Strachan, Clausewitz’s On War, 104.