The tactics of the Civil War

The tactics of the Civil War

Page 1 of 2

Long neglected by military history, because it was no doubt seen as trivial and sometimes sordid, combat study as such was only rehabilitated relatively late. In France, it is generally associated with the First World War and with the current of the historial of Péronne, with a history of the conflict centered on the study of daily life, consciences and individuals rather than on that of campaigns and battles. . A vision defended in particular by the British historian John Keegan, world famous, or by the French Olivier Chaline, who calls it "the new battle-story" to better distinguish it from the old one - the latter made up of chronologies sometimes empty of meaning as evidenced by the famous phrase "1515 Marignan".

Old tactics

Now international, this trend was born in the United States, and it was the historical study of the Civil War that generated it. Through a process similar to that which will be found in France on the subject of the Great War, it was the gradual disappearance of the last veterans of the conflict, in the 1930s and 1940s, that led American historians to take an interest in their experiences. and their daily life as soldiers. Their memories, memories and testimonies passed from the status of autobiographical accounts to that of objects of history. One of the pioneers of this path was certainly Bell Irvin Wiley with his works on the daily life of “Johnny Reb” and “Billy Yank”, archetypes of southerner and northerner soldiers, published in 1943 and 1952 respectively.

Generally speaking, the soldier at war spends much more time walking or camping than fighting. In spite of this, the fight undoubtedly remains, in a war, the paroxysmal experience most striking for most of those who are confronted with it. As Chaline writes, "the battle is apocalypse in the sense of revelation - in other words, it is often in combat that the temperaments, personalities and ideals of those who wage it are revealed. Knowing the way they fight is therefore breaking into their lives as well as looking into other quieter aspects of their daily lives.

In 1861, tactics in general had changed little since the end of the Napoleonic Wars. We always fight in relatively small spaces, rarely exceeding 150 or 200 square kilometers. The units remain in tight formations, as they almost always have been since ancient times. The reason for this situation is essentially practical. In the absence of other means, the transmission of orders is limited the visual and auditory capacities of those who receive them. On a mid-19th century battlefieldth century, obscured by the smoke from the use of gunpowder and invaded by the deafening din of artillery and musketry, these are bound to be very small.

The officer who must give orders to his soldiers must therefore keep them within earshot to do so, especially since the training of recruits does not emphasize individual initiative. If the regiments wear rather conspicuous uniforms and one, or even several flags, it is not out of coquetry but to be able to see each other and identify more easily. Conveying orders and information along the chain of command requires the use of mounted dispatch riders, carrying - when they manage to deliver them - oral or written instructions. As for the transmission by semaphore, it exists - and will be used with success by the Confederates at Bull Run in 1861 - but its use remains uncertain and limited, being dependent on the configuration of the ground and the visibility. All of these factors make it almost obligatory to fight in close order.

A war of infantry

Through the ages, theinfantry has more than earned its nickname "Queen of Battles", but this was perhaps never truer than during the Civil War. The latter was really a war of infantry. McPherson estimated that the proportion of infantry in the total strength of the two armies was in the order of 85% for the Federals, perhaps a little less for the Confederates who made more use of the cavalry. In the north alone, nearly 2,000 regiments and various units were formed during the war, and of this total, approximately 1,700 were infantry. While until then the cavalry had often played a decisive role even though they were already in the minority, it was the infantry that essentially won the Civil War.

The reasons are varied. The technical improvement of firearms has made a major contribution to this. By their increased range, rifles and rifled cannons made the battlefield a much more dangerous place than it had been half a century earlier. Where spherical musket bullets were hardly dangerous beyond a hundred yards, the Minié bullets from rifled rifles are precise to 200 yards, easily reach 500 and, in a suitable rifle in the hands of a expert shooter, can still hit the target at nearly a kilometer. In the face of such fire, a traditional cavalry charge was likely to be decimated before it even came into contact with the enemy.

As for the artillery, it was the geography which prevented him from giving his full potential during the conflict. Napoleon Bonaparte, himself a trained artilleryman, had made it an important tool of his victories, capable of weakening the enemy before the cavalry charges which would then break him. The advancements the rifled guns brought in both range and firepower should have made it deadly on the battlefields of the Civil War. However, it was rarely so.

In 1861, the United States was still largely forest coveredeven on the east coast. Limiting visual range, this feature will prevent artillery from performing to their full potential. In the absence of communications to use forward observers, indirect fire is limited to siege warfare, and field guns can only open fire on targets their servants see. Another problem concerned the overall mediocrity of the road and local network, an obstacle to the easy movement of artillery and a fortiori to his concentration.

Forced to move dangerously close to enemy lines in order to pound them, the gunners were therefore subject to infantry fire much more often than in the past, and they were among the prime targets of snipers. In short, the Civil War was fought at a time and under circumstances when the infantry was already notoriously better armed than before, relegating the cavalry to a secondary role, and where the artillery did not yet have the firepower. murderer that she would have acquired half a century later. The context was therefore particularly favorable for the infantry dominates the battlefield.

Maneuver in column

To all lord, all honor, therefore. On the eve of the war, the training and tactical employment of the infantry in the United States rested primarily on two manuals. The first had been written in 1835 by Winfield Scott and essentially endorsed the tactics of the Napoleonic Wars. It had been the norm during the war with Mexico, a type of conflict to which it suited very well - although it was mostly the artillery that had worked wonders in the American camp. This manual had been replaced in 1855 by another, the work of Captain William Hardee. Combined with the adoption of the Springfield Model 1855 rifle, a maneuverable and relatively short rifled barrel weapon, the Hardee Manual emphasized the rapidity of movement and tactics of the light infantry. It was updated in 1862, in the north, by Silas Casey, to incorporate the use of the Springfield Model 1861, which is longer and slightly different.

In both, the French influence is obvious. In addition to the peculiarities of the Hardee manual concerning light infantry, to which we will return, in Scott we find tactics similar to those which Napoleon Bonaparte had employed and refined half a century earlier. Thus, the basic training is the column. Usually four rows in front, it is mainly used for movement (column of road) and maneuver. It is, however, hardly used in combat anymore. At the start of the Revolutionary and Empire wars, it was still the privileged attack formation of the infantry, allowing the full weight of a bayonet charge to be weighed on a precise point of the opposing line. .

However, the enormous gaps made in Borodino (1812) in the columns of the French infantry by the Russian guns, persuaded the tacticians of all countries that the column assault was no longer a viable solution against a position with a adequate artillery support. The advent of rifled guns only made the problem worse. The column therefore served primarily, during the Civil War, to move. In this regard, it should be noted that a regiment of several hundred men placed in columns of four already occupies a certain length. Multiply by an average of four regiments per brigade, three brigades per division and three divisions per army corps, and we can imagine the considerable length (several kilometers) over which an army on the march could stretch. - not to mention artillery teams and hundreds of carts carrying food, ammunition and various equipment.

On the bad roads of the time, listed on maps that were often approximate - when there were any - and rarely kept up to date, such columns could cause gigantic traffic jamsso that just moving an army was sometimes quite an accomplishment. For the soldiers, these marches were not easy. Of course, they weren't forced to keep pace: even the instruction manuals, anxious to save their strength, recommended that it be used only for maneuvers and assaults. However, their heavy woolen uniforms were ill-suited to the summer heat of the North American climate, and they suffered considerably from sunstroke and heatstroke.

Fight online

The combat formation par excellence was therefore the line, two rows deep. This had gradually replaced the line of three rows in use until the beginning of the 19th century. As Napoleon I noticeder himself, a line three ranks deep was less advantageous, because in firing the third rank had to pay more attention not to injure the men in the front rank than to aim correctly. At the same time, a line of three ranks offered little more chance of withstanding a bayonet charge.

The main advantage of the line was that it allowed to fully exploit the firepower infantry, which became particularly crucial with the advent of rifled rifles. In addition, the broad front it presented reduced the effectiveness of enemy artillery fire: while the target it represented was larger, it was also more dispersed. Thus, each individual cannon shot caused fewer casualties in its ranks. The major flaw of the line was its thinness, which made it vulnerable to a melee attack.

The latter, however, were very rare during the Civil War. They already are generally: more often than not, if the attacker is not repelled, the defenders instinctively withdraw before contact. As recent combat studies have shown, only one in ten assaults end in melee engagement. In the end, that makes sense, as bayonet skipping is an even more unnatural activity than shooting yourself standing in tight rows. For this reason, the fighting in body to body Usually ended fairly quickly, with either party fleeing or surrendering. The losses they caused were no less severe, as this type of engagement remained, in essence, brutal.

For the reasons already mentioned, cavalry charges were even rarer, especially against positions defended by infantry. As a result, the iconic square formation typical of the Napoleonic wars lost its usefulness, and was hardly ever used. However, there was an alternative to the line: the column by company. In this formation, the companies that make up each regiment are deployed in a line in a single rank, but they are placed one behind the other rather than side by side. This gives a line ten rows deep instead of two.

The company column, a hybrid between the line and the assault column, was sometimes employed when commanders wanted to focus their attacking force on a given point in enemy lines, in a home assault. bayonet. The initial idea was laudable: it was to prevent the attack from turning into a long and deadly exchange of fire, rarely decisive, especially for the attackers. Nonetheless, such a tactic, like the column attack, offered a prime target for enemy artillery, and the few attempts generally ended in disaster.

During the battle ofAntietam (September 17, 1862), for example, General Mansfield in this way deployed the XIIth Northerner corps, largely made up of inexperienced recruits, and led him into the attack. Southern cannons and infantry greeted him with hellfire: the corps was quickly knocked out and Mansfield himself was fatally wounded. Even the IIth Union corps, until then considered an elite unit, was decimated in a similar attack at Spotsylvania Court House on May 9, 1864. Not only did the assault fail to remove the Southern position, but the IIth body suffered such losses that it was, thereafter, only a shadow of what it had been until then.

Much more than the shock, it isfire which will be used during the Civil War. At the regimental level, the manuals in force give the colonel a fairly wide range of possibilities in its use. If he wants to maintain a continuous fire, he can thus order one shot per file: the two men forming the right end of the line fire, then their two neighbors on the left, and so on until the whole regiment did the same. Rank shooting is also used. In this case, the back row opens fire first, then the front row.


There is also company fire - each of the ten or twelve companies in the regiment open fire one after the other - and wing fire, with the two right and left halves of the regiment firing in succession. We will add, of course, the firing by salvo, where the whole regiment fires like one man. However, the application of these different procedures required a certaindisciplined, which the volunteers who made up the bulk of the American Civil War armies had great difficulty in acquiring. More often than not, only the first shot was fired in a salvo, with officers then letting the soldiers reload and fire as they pleased - that is, more often than not, as fast (and poorly) as they wanted. could.

Compared to European armies still regulated like clocks, this apparent indiscipline never ceases to surprise. Its causes are diverse. There is thus, probably, a "cultural" dimension, if we dare say so. The volunteer armies of 1861 are still the direct heirs of those who fought in the War of Independence. Thesecitizen soldiers, who still elected (at the start of the war) their officers, only agreed to carry out orders up to a point, and it took time to develop them into disciplined fighters. It is no coincidence that the first months of the war saw the flowering of several instruction manuals specifically adapted to volunteers. In addition, during the battles for the War of Independence and then the Indian Wars, themarksmanship, individual marksmanship, took precedence over mass effect.

There are other reasons, technical and doctrinal. Salvo fire had been adopted to compensate for the reduced accuracy and range of smoothbore muskets: a volley of bullets was more likely to have a significant effect on the enemy than individual fire. The rifled guns had made this arrangement superfluous. The guns were now precise and powerful enough to take a shot "at will Can be effective. In addition, the Hardee Manual emphasized light infantry tactics, in which salvo firing was incidental, and which gave more control over the soldier's neck to control his fire.

It is interesting to note that despite everything, the infantry fire remained, in absolute terms,quite inefficient. In the North alone, nearly two billion cartridges were manufactured, and hundreds of millions of them, at the very least, were fired. Between May and September 1864 alone, the three northern armies of the Mississippi Military Department used more than 20 million. Despite this, the total number of killed and wounded, mostly from gunfire, did not exceed a few hundred thousand. As a result, it can be reasonably estimated that the shooting success rate was in the order of one in a thousand. This was nevertheless sufficient to ensure the conflict its bloody character.

Attack: squaring the circle

At the brigade level, the commanding officer has complete discretion as todeploymentof his strength. Having your regiments on the same line will have the advantage of using all of their firepower immediately and at best. Keeping one or more in reserve on a second line can be advantageous whether in defense, to reinforce a more fragile sector, or in attack - in order to be able to put the weight on a weak point of the enemy device once that this one has been spotted. One of the regiments can also be deployed in front of the main line, as skirmishers: it will act as a reconnaissance element (in attack) or as an advanced picket (in defense).

It is also possible to have regiments, or even brigades (in the case of a division) one behind the other, in order to allow an assault broken down intoseveral waves. In theory, this tactic could be a good way to saturate enemy defenses. In practice, it proved difficult to implement, as the first line, once blocked in its tracks, prevented the following ones from advancing. The Northerners experienced this at Fredericksburg (December 13, 1862), where 14 brigades successively assaulted the southern positions. Each was quickly blocked by the previous one, all under deadly fire from the defenders.

Among the solutions considered to deal with the improvement in firearms during the first half of the 19th centuryth century, there was simply ...walk faster. Until then, military units have been marching slowly, at a rate of around 75 to 80 steps per minute. Even in combat, they spent little time within shooting range of the enemy and did not need to come close any faster. When percussion locks increased the rate of fire, and rifled weapons increased their range, things changed. The armies adopted a sustained step (quicktime in English), significantly faster: around 120 movements per minute. This is still the regulatory rate in most armies around the world today. Only a few units have kept the old slow pace, the best known being the French Foreign Legion.

The steady step was therefore the standard approach of the Civil War soldier in combat. If necessary, we could resort toin gymnastics (double quick). Strictly speaking, it was no longer walking: at 165 paces / minute, the soldiers were trotting. It wasn't a race either. It was, in fact, not possible to increase the pace any further without risking losing the cohesion of the unit. Incidentally, running with a rifle on the shoulder (as prescribed by the manuals) was quite impractical. It was therefore desirable only in the last few yards of a charge, just before contact with the enemy - if the enemy had not slipped away.

Bury to survive

If offensive tactics proved so problematic during the Civil War, it is also because the conflict saw the large-scale use of a new element, which would revolutionize the art of warfare for decades to come. :countryside fortification. A trend that had already started a few years earlier during the Crimean War, but which most observers had failed to understand, mainly because military operations there had largely been confused with the siege of Sevastopol.

Until then, non-permanent fortifications - redoubts, parapets, abatis, trenches, earth forts - had mainly been used for siege warfare. They allowed them to approach enemy ramparts while remaining in cover, and to position their artillery safe from enemy guns. These earthworks became an essential part of thepoliorceticin modern times, so much so that the phrase "opening the trench" has become synonymous with starting a siege.

Despite everything, they had also served, occasionally, in the open countryside. A defensive army could use them to strengthen its position. The construction offearswas particularly useful for guarding or blocking an obligatory crossing point, such as those set up by the Russians at Borodino on the road to Moscow, and which the French captured in 1812 at the end of one of the bloodiest pitched battles Of the history. Nevertheless, the relative ineffectiveness of the muskets did not necessitate, then, to constantly seek cover.

As for artillery fire, its effects could be largely mitigated by placing troops slightly behind a ridge line. This tactic ofreverse slope, popularized by the Duke of Wellington during his campaigns in the Iberian Peninsula, will be successfully reused by "Stonewall Jackson in one of the first major battles of the Civil War, Bull Run (July 21, 1861). In general, the exposure to fire was brief enough that digging entrenchments during battles which, moreover, seldom lasted more than a day, was considered superfluous.

But rifled firearms were going to be a game changer. With rifles that could have a working range of over 500 meters, and cannons that remained accurate for up to two kilometers or even beyond, the battlefield became a much more dangerous place than it had been before. The fighter, who until then was hardly exposed except during the last phase of an assault, was nowhere safe. Soldiers and officers therefore learned, during the conflict, tolook for cover whenever it was possible.

Another determining factor was the very nature of the training given to officers before the war. Although it was a versatile cadre, West Point Military Academy's education primarily emphasized the tactics and techniques of the military.genius. The country's defense rested primarily on its system of coastal fortifications, and West Point was therefore training military engineers to build and maintain it. It is no coincidence that many of the officers who left the academy then left the military to become civil engineers.

These West Point graduates formed the bulk of the generals who served on both sides during the war. Their training therefore inclined them to establishfortificationsprovisional as soon as they could, and shovel and pickax quickly became as familiar to the soldiers as their rifles or rucksacks were. Robert Lee thus earned among his men the unpleasant nickname of "the ace of spades" (ace of spades in English ; this is a play on words becausespade also means "shovel") after having surrounded Savannah, then Richmond, with miles of trenches and countless forts and batteries at the start of the war.

Initially, the fighters used whatever they could find as cover on the battlefield:fences and low walls abounded in farmland, and even a sunken road could offer excellent protection - as was the case in Shiloh (April 6-7, 1862) and Antietam (September 17, 1862). The embankment of an unfinished railway line even served as an entrenchment during the second battle of Bull Run, in August 1862. With a minimum of development, these elements of the battlefield could even become formidable fortified positions, as was the case with the stone wall running along Marye's Heights in Fredericksburg or that capping Cemetery Ridge in Gettysburg (July 1-3, 1863).

The end of the war saw the spread of more elaborate entrenchments, making the assaults particularly deadly and forcing the attacker to establish a real siege if he could not bypass the obstacle. The lines that the Confederates had fortified around Spotsylvania Court House were the scene of one of the fiercest battles of the entire war in May 1864, and by the following month the Battle of Petersburg froze ina trench war prefiguring, fifty years in advance, that which would characterize the Great War.

If it was, for the most part, delivered with the traditional tactics of the heavy infantry, the Civil War nevertheless reserved a notable place for those, more recent, oflight infantry. The influence of the Hardee manual of 1855, already mentioned, was all the more important because during the preceding decade, the federal infantry had hardly faced any but the Amerindians, against whom the combat was more often reduced to dispersed skirmishes.

French fashion

As in many other areas of the military, the US military was then largely influenced by its French counterpart. The prestige of the latter, despite its final defeat in 1815, was then unmatched. It then remained on a series of victories, won against the Dutch (siege of Antwerp, 1832), the Russians (Crimean War, 1853-56) and the Austrians (Italian War, 1859), not to mention the conquest of Algeria (from 1830). The French army was considered above all to be at the forefront of modernity, both technically and tactically, and was therefore seen asa model to follow.

It was also from France that interest in the light infantry came. From the wars of the Revolution and the Empire, the French army created light infantry regiments, distinct from those of line infantry. Their training emphasized speed of movement and precision in the individual shot. These units were used primarily for maneuvers requiringfast travel, especially in difficult terrain, as well as to cover the army’s flanks and conduct reconnaissance and harassment operations. However, outside of these missions, these regiments fought in close ranks, like the line infantry.

Things changed from 1838 under the leadership of the Duke of Orleans, the eldest son of King Louis-Philippe. From his experience as an officer in Algeria, the young prince had drawn the idea of ​​fighting the light infantryin dispersed order, not only during specific missions, but permanently. He created that year the first battalions of hunters on foot. Freed from the obligation to fight in line, these soldiers had to run around, could fire at will and were encouraged to take initiatives - something relatively new as the European armies had, until then, operated in a rigid respect for the chain of command.

The hunters on foot relied on their speed of movement and use of cover to get closer to enemy lines, and on their best marksmanship training to bring down their adversaries. In theory, they could thus gain the upper hand over the line infantry while limiting their losses. In practice, this conceptne résista pas à l’épreuve des faits. Les armées européennes déployaient désormais une puissance de feu autrement supérieure à celle des guerriers d’Abd-el-Kader en Algérie. L’expérience de la guerre de Crimée, face aux tranchées qui ceinturaient Sébastopol, montra aux Français qu’ils avaient fait fausse route, et les chasseurs à pied apprirent à « rentrer dans le rang » au sens littéral du terme.

Une utilisation problématique

Ironiquement, les Américains commencèrent à s’intéresser aux tactiques de l’infanterie légère au moment précis où l’armée française était sur le point de les délaisser. Le fusil Springfield modèle 1855, doté d’un canon relativement court lui conférant une meilleure maniabilité que les mousquets traditionnels, se prêtait admirablement à ce type de combat. En outre, les engagements contre les Indiens présentaient de grandes similitudes avec ceux que les Français avaient livrés en Algérie. Le contexte se prêtait donc à diffuser au sein de l’armée américaine la « mode » des chasseurs à pied.

Le manuel Hardee consacrait donc d’importants passages à la formation en ligne de tirailleurs (skirmish line). Il s’agit d’une ligne simple et clairsemée, au sein de laquelle les soldats sont espacés d’au moins un yard (0,91 m), généralement deux. Ainsi déployé, un régiment peut facilement couvrir le front d’une brigade entière. Les tirailleurs peuvent ainsi tenir l’ennemi à distance tandis que la brigade s’organise, mener des reconnaissances – surtout en l’absence de cavalerie – ou bien harceler l’adversaire. Ils étaient, chose relativement nouvelle, entraînés à se servir du couvert et même à faire feu en position couchée.

La ligne de tirailleurs fut abondamment utilisée au cours de la guerre, même si elle ne fut jamais la formation principale de l’infanterie. De fait, disperser les hommes revenait aussi à éparpiller leur puissance de feu, et on a vu que sans un entraînement adéquat – dont les volontaires bénéficiaient rarement – l’habileté au tir des combattants était toute relative. Malgré tout, la ligne de tirailleurs se montra utile et parfois même décisive en plusieurs occasions, comme à Chancellorsville (3 mai 1863) où deux régiments nordistes déployés de cette manière ralentirent suffisamment la progression des Confédérés pour permettre à l’Union de s’établir sur une nouvelle ligne de défense.

Une telle formation n’était cependant guère adaptée à l’offensive. Il y eut bien quelques tentatives pour employer les tactiques de l’infanterie légère à plus grande échelle. La plus connue est celle faite par le colonel nordiste Morgan Smith durant la bataille du fort Donelson (15 février 1862). Smith, qui se tenait crânement à cheval derrière son régiment de tête, avait ordonné à celui-ci de progresser par bonds successifs, courant quelques dizaines de mètres avant de se mettre à plat ventre pour éviter les salves de l’ennemi. Ses hommes purent ainsi s’approcher des retranchements adverses et les prendre d’assaut en limitant leurs pertes.

Malgré ce succès, cette tactique ne sera que rarement employée par la suite. Les officiers voyaient en effet avec un certain scepticisme une formation où les soldats risquaient d’échapper à leur contrôle direct. De surcroît, elle était vue comme étant de nature à nuire à la cohésion de l’unité. Combattre efficacement de cette manière nécessitait un entraînement prolongé que les volontaires de la guerre de sécession ne possédaient pas. Enfin – et surtout – le succès de cette tactique reposait sur l’utilisation par l’adversaire d’un feu de salve, qui permettait à l’assaillant d’avancer pendant que les défenseurs rechargeaient leur fusil. Un tir par file ou à volonté annulait l’effet escompté, et l’apparition d’armes à répétition, vers la fin du conflit, ne fit qu’aggraver le problème. Si les soldats se couchèrent fréquemment, ce fut le plus souvent en défense, pour échapper au tir de l’artillerie en l’absence d’autre couvert, ou pour se dissimuler.

Tireurs d’élite

Une des nombreuses nouveautés de la guerre de sécession fut le recours élargi aux tireurs de précision. Le concept n’était pas nouveau, pas plus que les armes rayées d’ailleurs. Des fusils rayés existaient dès le XVIIIth siècle, mais leurs balles sphériques devaient être littéralement forcées dans le canon, ce qui impliquait un rechargement de l’arme difficile et long, toutes choses peu pratiques sur un champ de bataille. Pour cette raison, ces armes n’étaient distribuées qu’à quelques très bons tireurs et n’étaient par conséquent employées qu’à très petite échelle.

L’invention de la balle Minié permit la généralisation du fusil rayé, changeant ainsi la donne en permettant la fabrication d’armes très précises et d’utilisation plus aisée. Dès le début de la guerre de Sécession apparut l’idée de former des unités entières constituées de tireurs d’élite. Hiram Berdan, un ingénieur qui passait pour être le meilleur tireur de l’État de New York, proposa au département de la Guerre la création d’un régiment constitué des meilleurs tireurs de tout le pays. Le président Lincoln ayant intercédé en sa faveur, Berdan obtint rapidement gain de cause. Pour être enrôlé, chaque candidat devait se montrer capable de placer consécutivement dix balles à l’intérieur d’un cercle de 25 centimètres placé à 180 mètres de distance.

L’initiative eut un tel succès qu’on eut assez de soldats pour former non pas un, mais deux régiments, désignés 1er et 2thU.S. Sharpshooters regiments. Ces « tireurs de précision » (sharp signifiant « précis » en anglais) furent dotés d’uniformes verts pour leur permettre de se soustraire plus aisément à la vue de l’ennemi : une des premières tentatives d’utilisation du camouflage sur un champ de bataille, même si elle demeura limitée à ces deux seules unités. Initialement priés d’amener leurs propres armes, souvent des fusils de chasse, les recrues furent ensuite dotées d’une version spécialement modifiée du fusil Sharps modèle 1859.

Réputée pour sa précision, cette arme était à chargement par la culasse, ce qui lui permettait une cadence de tir allant jusqu’à 9 coups/minute. Berdan demanda notamment à son concepteur, Christian Sharps, d’en remplacer l’encombrant sabre-baïonnette par une baïonnette à douille. Il lui fit également installer un viseur métallique amovible, et modifier la hausse de sorte qu’elle permette de viser jusqu’à 1.000 yards, soit plus de 900 mètres. Ces modifications firent grimper le coût unitaire du fusil de 35 à plus de 45 dollars, contre 12 dollars pour un Springfield modèle 1861. À cause de la cadence de tir élevée de leur fusil, les Sharpshooters de Berdan se virent distribuer 100 cartouches par homme, là où le fantassin de base n’en recevait que 40.

Au grand déplaisir de Berdan – qui était colonel des deux régiments à la fois – ces unités ne furent jamais engagées en une seule brigade, comme il l'aurait souhaité, mais dispersées à travers toute l’armée du Potomac. Les compagnies furent détachées auprès des différents échelons de l’armée en fonction des besoins. Malgré tout, elles y excellèrent dans les rôles habituellement dévolus à l’infanterie déployée en tirailleurs. Elles se firent surtout une spécialité d’abattre les servants de l’artillerie ennemie, les officiers, les estafettes transmettant les ordres.

Leur feu précis, dense et meurtrier les vit rapidement être imitées, et d’autres unités du même genre furent créées. Dans l’Ouest furent ainsi employés le 64th régiment de l’Illinois et le 1er régiment du Michigan, dont une des compagnies était constituée d’Amérindiens. Les Sudistes ne furent pas en reste, créant par exemple les Palmetto Sharpshooters de Caroline du Sud. Les quelques centaines d’exemplaires du fusil Whitworth que les Confédérés purent importer de Grande-Bretagne leur furent distribués en priorité. Dans les deux camps, certains tireurs assortirent des lunettes nettes télescopiques à leur fusil, mais le caractère encombrant de ces premiers modèles – certaines étant plus longues que le fusil lui-même ! – rendait peu pratique leur utilisation au combat.

Pour Napoléon Bonaparte, la cavalerie était l’arme décisive du champ de bataille. C’étaient ses charges qui brisaient l’armée ennemie après que celle-ci eût été usée à ses points les plus faibles par des attaques d’infanterie et les tirs concentrés de l’artillerie. Par sa puissance de choc et sa capacité à poursuivre l’ennemi, elle pouvait muer sa retraite en déroute, lui causant des pertes élevées. La guerre de Sécession ne connut rien de tout cela. Cinquante années d’évolution militaire avaient réduit la cavalerie à un rôle secondaire, et les Américains furent parmi les premiers à en faire l’expérience.

Video: Strategy of the Civil War. The Civil War era 1844-1877. US History. Khan Academy