The First Modern War: The American Civil War, its Lessons and Challenges for Today’s Military Planners

Note: This article is one that I am preparing for my Gettysburg Staff Ride in early March. It is more academic and theoretical in its emphasis being directed at those who will be involved in the planning of joint operations at the operational level of war. 


Pickett’s Charge Showcased the Futility of Napoleonic Tactics Against Modern Weaponry

The American Civil War was the first modern war. It was a watershed time which introduced changes in tactics, logistics, communications and the concept of total war to the world. Though it did not change the essential nature of war, which Clausewitz says is “is an act of violence to compel our opponent to fulfil our will.”  What the war did was add new dimensions to war, increased its lethality and for the first time since the 30 Years’ War saw opponents take war to civilian populations as part of a military campaign.

The Civil War was a precursor to the wars that followed. However, like all wars many of its lessons were forgotten by military professionals in the United States as well as in Europe. Thus 50 years later during World War One, British, French, German, Austrian and Russian wasted vast amounts of manpower and destroyed the flower of a generation because they did not heed the lessons of the Civil War.

The lessons of the war are still relevant today. Despite vast advances in weaponry, technology and the distances with which force can be applied by opponents, war remains an act of violence to compel an enemy to fulfill our will. War according to Clausewitz is a “chameleon” which changes its nature to some degree in each particular case, but it is always characterized by the violence of its elements, the province of chance and its subordination to the political objective.

The study of the Civil War can be helpful to the joint planner and commander because it so wonderfully shows the interplay of Clausewitz’s Trinity during an era of great technological change. It is my intent to introduce the reader to the manner in which the military theory and doctrine that dominated American military thought before was applied and changed as a result of the experience gained during the war.


Dennis Hart Mahan’s Book: The First American Book on Military Theory

The professional American army officers on both sides were educated at West Point, VMI or the Citadel. In these institutions they were taught Henri Jomini’s interpretation of Napoleonic warfare and the theories of Dennis Hart Mahan and Henry Halleck.

The war exposed the serious weaknesses in all of these theories which were challenged by advances in weaponry and the vastness of the American continent.  During the war both Union and Confederate armies learned to value field fortifications and the limitations of the artillery of the day during offensive operations.

Logistics influenced campaigning on the American continent much more than previous European wars.  An example can be found in Lee’s Gettysburg Campaign where he had to travel far from his railheads and bases of supply, meaning that he had to live off the land in enemy territory. The concept of total war found its first application in the campaigns of General William Tecumseh Sherman and Robert E. Lee’s use of defensive maneuver and fortifications in positional warfare heralded a new era in warfare.

These factors influenced and affected the Union and Confederate armies as they campaigned. Likewise, the advances weaponry particularly the rifled musket, posed a conundrum for officers educated in the Napoleonic tactics that both armies began the war. Those tactics were developed at a time when the maximum effective range of muskets was barely 100 meters. Yet by 1860 the rifled muskets had an effective range of about 400 meters, and the advent of the repeating rifle increased the firepower available to individual soldiers.  Yet despite the increase in range and accuracy that came with the rifled musket tactics were slow to change.

Ante-bellum US Army leadership was most influenced by the theories of Henri Jomini, Clausewitz had yet to make his appearance in America. Dennis Hart Mahan, a professor at West Point challenged Jominian orthodoxy and modified the current orthodoxy by rejecting its central tenants-primarily offensive assault tactics.”[i] Thus there was a tension in American military thought between the followers of Jomini and Mahan. Conservative Jominian thinking predominated much of the Army, and within the army “Mahan’s decrees failed to win universal applause.”[ii]

However, Mahan did influence many future leaders of both the Union and Confederate armies who participated in his “Napoleon Club,” a military round table at West Point. [iii] Mahan’s greatest contributions were his development of the active defense and emphasis on victory through maneuver. Mahan’s thought contrasted with that of Jomini who thought maneuver was risky and believed that purpose of war was the “defeat of the enemy’s army.” As we look the Gettysburg campaign it is important to note how much Lee was affected by the thought of Jomini as he attempted to defeat the Army of the Potomac, while ignoring the advice of Longstreet to use maneuver and active defense too his advantage.

Mahan emphasized the use of “maneuver to occupy the enemy’s territory or strategic points.” [iv] Edward Hagerman wrestles with the disjointed developments in infantry, artillery and cavalry tactics of the ante-bellum Army in his book The American Civil War and the Origins of Modern Warfare.  Hagerman surmised that “Military thinking, and even more strategic organization, remained essentially within the Napoleonic tradition filtered through an eighteenth-century world view….” He asserted that “A broader vision was necessary to pose an alternative to the mechanistic program.”[v]

The leaders who organized the vast armies that fought during the war were influenced more than military factors. Social, political, economic, scientific and even religious factors influenced their conduct of the war. Commanders educated at West Point who had previously commanded small units were faced with the task of organizing, training and employing large armies made up primarily of militia units and volunteers. Most had little experience commanding such units and their experience with militia and volunteer formations during the Mexican War did not increase their appreciation for them or their leaders.


The 2nd Michigan Regiment: Most Civil War Units on both sides were State Regiments

Both armies were changed by the war. Initially both sides sought to fight the war with volunteers. The South began a draft first followed by the Union in 1863. At the beginning of the war General George McClellan successful fought the break-up of the Regular Army. He helped keep it separate from the militia units organized by the States. This preserved a professional core in a time where the new volunteer units were learning their craft. The Confederacy did not have a Regular Army and all of its units were raised by the States and officered by a collection of professionals from the Ante-bellum Army, militia officers, political appointees or anyone with enough money to raise a unit. The draft laws created much consternation in both the Union and Confederate States and the efforts to enforce the draft were filled with controversy and sometimes violence as was evidenced during the New York Draft Riots of 1863 where Union Soldiers, recently victorious at Gettysburg were employed to end the rioting and violence.


The Integration of Sea and Land Logistics Systems in the Civil War Revolutionized the Way that Modern War is Supplied

The Ante-bellum Army developed its logistic doctrine from Napoleonic examples. That doctrine had to be modified in light of the American reality of a less developed continent with far greater distances involved in the movement of troops. During the war, both armies learned to adapt their logistical support services to the reality of war.


Railways Meant the Ability to Move Troops and Supplies Great Distances very Quickly

Where possible each side used railroads and maritime forces to move troops and supplies. The Confederacy, lacking in both was at a severe disadvantage. The Union however enjoyed a great advantage in modern rail networks, as well as ocean and river based maritime power. By late 1863 the Army of the Potomac, as well as forces in the West demonstrated “the close integration of operational planning and that of the general in chief and supply bureaus. In this one area, the development of a mature and modern staff was evident.”[vi]

In both armies commanders and their logisticians experimented with the number of wagons per regiment and how army commanders, modified that number at various points during the war based on their situation. Both armies experimented with the use of the “flying column” as a response to the dependency on wagons. The basic load of food and ammunition carried by each soldier in order to increase strategic maneuverability was adjusted to meet the operational need. Both armies often had to live off the land. The success and failure of forage operations and the requirements for people and animals in each theater of operations had a large impact on each army.

The size of the armies and the distances involved on the battlefield made command and control difficult.  As such communications became more important and each army experimented with new signals organizations that used both old and new communication technologies. At the beginning of the war both sides made extensive use of visual signals and couriers, but rapidly began to rely on the telegraph for rapid communications.


Signal Corps Soldiers and Wire Communications

The organizational tension was particularly evident in the rivalry between the U.S. Army Signal Corps and the Military Telegraph Service.  The Signal Corps focused on wireless communications. It preferred the Beardslee wireless telegraphs which had the limitations of such early wireless technology. The Army command favored the traditional wire bound networks operated by the Military Telegraph due to better reliability and security. Though the Army rejected the Beardslee equipment some commanders requested it for their operations. [vii] As each Army became more dependent on the telegraph, each feared that their signals could be compromised through wiretapping and made efforts to encode their transmissions.


The Beardslee Wireless Telegraph 

The evolution of how Union and Confederate armies used field fortifications is an interesting topic. McClellan made extensive use of them on the Peninsula in 1861 and Lee made sporadic use of them [viii] until 1864.  Lee made much more use of field fortifications during the Wilderness campaign, the battles around Richmond culminating in the defense of Petersburg.  The developments in field works and firepower gave the advantage to the defense. This was especially the case when opposing armies made the frontal attacks which were at the heart of Jominian offensive tactics.  Early in the war commanders including Grant at Shiloh and Lee at Antietam failed to dig in, but over time both the Union and Confederate armies learned to dig hasty field works as a matter of course.[ix]


Massive Siege Mortar outside Petersburg

Both sides also learned to use maneuver in combination with positional warfare to force the enemy to battle. Hagerman examines the campaigns in the West of Grant, Sherman and Rosencrans, particularly Stone’s River, the Vicksburg Campaign, and the campaign in middle Tennessee.[x] The last two chapters of Hagerman’s book detail these issues in the context of the 1864-65 campaign around Richmond and Sherman’s campaigns in Georgia and the Carolinas. Of particular note is how Sherman’s forces routinely entrenched on the offensive [xi] and how Confederate forces under Joseph Johnston employed entrenchments on the defensive.

civil-war-earthworks-petersburg Petersburg Fortifications a Harbinger of World War One

Surprisingly, it was Confederate Cavalry commander Joe Wheeler toward the end of the war made use of entrenchments, something not seen before by an arm traditionally known fro maneuver. Hagerman noted that Confederate Cavalry “perhaps best displayed the growing intensity of trench warfare” [xii] by the latter part of the war.

The Corps of Engineers in both armies adapted to the war. Prior to the war the Corps of Engineers was primarily responsible for building coastal fortifications and outposts in the west.  Both sides had to develop Engineer or Pioneer units from scratch in 1861.By the middle of the war organized units of Pioneers and Engineers were enhancing both offensive and defensive operations.


Engineering Units were Built from Scratch and Accomplished Many Feats

The Corps of Engineers initially had a difficult time adapting to war. The dispersion of the Corps among the line and its civil duties were impediments to responding to the needs of war.  There was a hesitancy and resistance to creating engineering units by Congress, despite the pleas of McClellan and Lincoln for specialized engineering units.[xiii] When they were established it was ironic how the newly organized engineer units had few very few West Point trained Corps of Engineers officers. Most Union Engineer Units were primarily staffed and commanded by officers detailed from the line or who had come from civilian life. The effect was a “decline in the antebellum definition of professionalism embodied in the Corps of Engineers” [xiv] which prior to the war were considered the elite branch of the Army.

Strategy and operational level adapted to the new reality of war. Attrition and exhaustion became as important in relation to both positional and maneuver warfare. In 1864 in the East the “ascendancy of positional warfare” allowed Lee to hold out and force Grant into winter quarters at Petersburg.[xv] This demonstrated that “an army fighting on interior lines, even under nearly overwhelming conditions of deprivation and against vastly superior numbers, could sustain a prolonged existence by use of field fortification and defensive maneuver.”[xvi]


Sherman’s March to the Sea

Despite the increasing power of positional warfare in relation to fortifications in the East and around Atlanta, maneuver was not ignored. Sherman’s campaign in Georgia and the Carolinas demonstrated how an army could exploit “diversion, dispersion, and surprise to successfully pursue a modern total-war strategy of exhaustion against the enemy’s resources, communications and will.”[xvii] Sherman used maneuver to force his opponents out of their prepared positions and did not hesitate to target the key infrastructure and infrastructure needed by the Confederate armies. The same was true in Virginia where in 1864 General Phillip Sheridan laid waste to the Shenandoah Valley, the breadbasket of the Army of Northern Virginia.

The developments in tactics, maneuver, defense and logistics and how those were developed over the course of the war brought about a form of warfare that remained dominant of decades. In studying the campaigns, developments and tensions between the theories of Jomini and Mahan in the Civil War a student can begin to recognize them in future wars fought by the US Army including World War Two.

Russell Weigley picks up this theme in his book The American Way of War. Weigley  discusses Grant’s strategy of annihilation and its costs as well as Sherman’s campaign against Johnston and his attack upon Southern resources.[xviii] Weigley’s discussion of tactics used by both sides in the Civil War reflects the thought of British theoretician of J.F.C. Fuller. Fuller noted that “the tactics of this war were not discovered through reflection, but through trial and error.”[xix]

It is important for planners and commanders at the operational level to see the importance the developments of the Civil War on how we campaign today. While the technology is now antiquated, the ideas are not. The campaigns of Grant and Sherman in particular influence modern strategy.  This is reflected the Marine Corps which discusses the maneuver and attrition warfare continuum in MCDP 1 Warfighting.[xx] It is important for students of operational art to be able recognize the these developments and principles in what we do today, to see the logical development of each of these elements in modern war and to find new ways to apply them within the scope of the technologies we now use that those that will be available in the coming years.


The Destruction of Hood’s Ordnance Train Outside Atlanta

The important things that we learn from studying the various campaigns of the Civil War are timeless. If we only focus on the military aspects of the great battles we miss the really important lessons. The battles and leadership lessons that we learn from them are important. However it is the often arcane but important subjects such as transportation, logistics, communications and fortifications, as well as the diplomatic, economic and informational aspects of the war that are more important.

In his book Hagerman makes an astute observation on how change comes to military organizations. At the end of his discussion of the Corps of Engineers and the Army following the war, he notes “that change in war requires time for digestion before lessons are converted-if they are converted-into theory and doctrine.” [xxi] Such is true in every war.

When the United States entered ground combat operations in the First World War, General John Pershing’s strategy revisited some of the worst mistakes of the Civil War, as well as the bloody lessons learned by the Europeans during the first three years of that war. In light of this one wonders if the lessons were ever fully digested by the Army.


Irregular Formations Such as Mosby’s Raiders Would Create Problems Behind Union Lines, much Like Insurgents in Iraq and Afghanistan 

Such an observation can be made about our present wars. We need to ask if the lessons of previous insurgencies have been digested, even going back to the lessons of the Union Army operating in the hostile lands of the conquered Confederacy.[xxii] Likewise it is fair game for us to examine how our military adjusts to developments in weaponry, technology and tactics today in relation to past examples. Such studies must include regular and irregular warfare. Thus when we look at the Civil War, it is important to use those lessons to better understand the timeless aspects of military history, theory, doctrinal development, logistics, communications and experiential learning in war.

If we do not believe that we can learn from history we will in the words of historian George Santayana “be doomed to repeat it.”


Padre Steve+


[i] Hagerman, Edward. The American Civil War and the Origins of Modern Warfare. Midland Book Editions, Indiana University Press. Bloomington IN. 1992. p.9

[ii] Ibid. p.13.

[iii] Hagerman also notes the contributions of Henry Halleck and his Elements of Military Art and Science published in 1846 (p.14) and his influence on many American Officers.  Weigley in his essay in Peter Paret’s Makers of Modern Strategy would disagree with Hagerman who notes that in Halleck’s own words that his work was a “compendium of contemporary ideas, with no attempt at originality.” (p.14) Weigley taking exception gives credit to Halleck for “his efforts to deal in his own book with particularly American military issues.” Paret, Peter editor. Makers of Modern Strategy: For Machiavelli to the Nuclear Age Princeton University Press, Princeton NJ 1986 p.416.

[iv] Ibid.

[v] Ibid. p.27.

[vi] Ibid. p.79.

[vii] Ibid. p.87.

[viii] The most notable use of them between the Peninsula campaign and the Wilderness was at Fredericksburg by Longstreet’s Corps. Many wonder why Lee failed to entrench at Antietam.

[ix] Fuller, J.F.C. Grant and Lee: A Study in Personality and Generalship, Indiana University Press, Bloomington IN 1957.  Fuller comments “Thus over a year of bitter fighting was necessary to open the eyes of both sides to the fact that the trench was a by product of the rifle bullet, and like so many by-products, as valuable as the product itself.” (p.269) He calls it “astonishing that Lee, an engineering officer, made no use of entrenchments at the battle of Antietam.” (pp.269-270)

[x] Ibid. pp. 198-219.

[xi] Ibid. p.295.  Hagerman comments how Sherman’s troops outside Atlanta began to entrench both the front and rear of their positions.

[xii] Ibid. p.297-298.

[xiii] Ibid. p.238.

[xiv] Ibid.

[xv] Ibid. p.272

[xvi] Ibid. p.274.

[xvii] Ibid. p.293.  B.H. Liddell-Hart in comparing the campaigns of Grant and Sherman makes an important note that Sherman’s strategy is more “suited to the psychology of a democracy…” and “ he who pays the piper calls the tune, and that strategists might be better paid in kind if they attuned their strategy, so far as rightly possible, to the popular ear.” Liddell-Hart, B.H. Strategy Faber and Faber Ltd, London 1954 and 1967, Signet Edition, The New American Library, New York 1974 p.132

[xviii] Weigley, Russell F. The American Way of War: A History of United States Military History and Policy University of Indiana Press, Bloomington IN, 1973. pp.145-146.

[xix] Ibid. Fuller. P.269  A similar comment might be made of most wars including the current Iraq war.

[xx] ___________. MCDP-1 Warfighting. United States Marine Corps, Washington D.C. 1997. pp. 36-39

[xxi] Ibid. Hagerman. P.239

[xxii] Ibid. Fuller. Fuller’s comments on the situation of the Northern Soldier are eerily similar to our current conflict in Iraq : “Consequently, minor tactics were definitely against the Northern soldier, because his major tactics demanded the offensive; for without the offensive the South could not be brought to heel.  It was the problem which had faced the French in LaVendee and in the Peninsula of Spain, which faced Napoleon in Russia, and the British in South Africa during the Boer War of 1899-1902. Not only was the Northern soldier, through force of circumstances, compelled to fight in the enemy’s country, but he was compelled to devastate it as well as conquer it, in order to protect himself against the bands of irregular troops which were here, there and everywhere.” pp.247-248


Fuller, J.F.C. Grant and Lee: A Study in Personality and Generalship, Indiana University Press, Bloomington IN 1957

Hagerman, Edward. The American Civil War and the Origins of Modern Warfare. Midland Book Editions, Indiana University Press. Bloomington IN. 1992

Liddell-Hart, B.H. Strategy Faber and Faber Ltd, London 1954 and 1967, Signet Edition, The New American Library, New York 1974

Paret, Peter editor. Makers of Modern Strategy: From Machiavelli to the Nuclear Age Princeton University Press, Princeton NJ 1986

Weigley, Russell F. The American Way of War: A History of United States Military History and Policy University of Indiana Press, Bloomington IN, 1973

___________. MCDP-1 Warfighting. United States Marine Corps, Washington D.C. 1997

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