In the battles of 1861 and 1862, both sides employed the tactics proven in the Mexican-American War and found that the tactical offensive could still be successful but only at a great cost in casualties. Men wielding rifled weapons in the defense generally ripped frontal assaults to shreds, and if the attackers paused to exchange fire, the slaughter was even greater. Rifles also increased the relative numbers of defenders, since flanking units now engaged assaulting troops with a murderous enfilading fire. Defenders usually crippled the first assault line before a second line of attackers could come forward in support. This caused successive attacking lines to intermingle with survivors to their front, thereby destroying formations, command, and control. Although both sides favored the bayonet throughout the war, they quickly discovered that rifle-musket fire made successful bayonet attacks almost impossible.
As the infantry found the bayonet charge to be of little value against rifle-muskets, cavalry and artillery made troubling discoveries of their own. Cavalry soon learned that the old-style saber charge did not work against infantry armed with rifle-muskets. Cavalry, however, retained its traditional intelligence-gathering and screening roles whenever commanders chose to make the horsemen the "eyes and ears" of the army. Artillery, on its part, found that it could not maneuver freely to canister range as it had in Mexico because the rifle-musket was accurate beyond that distance. Worse yet, at ranges where gunners were safe from rifle fire, artillery shot, shell, and case were far less effective than close-range canister. Ironically, rifled cannon did not give the equivalent boost to artillery effectiveness that the rifle-musket gave to the infantry. Moreover, the increased range of cannons proved no real advantage in the broken and wooded terrain over which so many Civil War battles were fought.
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| Figure 1. Regimental line of battle from the march column of companies "A" through "J". When the line of battle was formed Companies "A" and "J" (who were usually issued the best weapons of the regiment) were deployed forward as skirmishers. Many Civil War regiments positioned color sergeants with small flank marker flags, general guide flags or cavalry guidons slightly forward and at either end of the main line of battle. These flags were used by the front ranks of the regiment to keep themselves in order and was also used to delineated the limits of the regiment to the field/division/corps commander. The regiment's "stand of colors" was always located near the center and slightly forward of the center of the battle line. |
There are several possible
reasons why Civil War commanders continued to employ the tactical offensive long
after it was clear that the defensive was superior. Most commanders believed the
offensive was the decisive form of battle. This lesson came straight from the
Napoleonic Wars and the Mexican-American War. Commanders who chose the tactical
offensive usually retained the initiative over defenders. Similarly, the
tactical defensive depended heavily on the enemy choosing to attack at a point
convenient to the defender and continuing to attack until badly defeated.
Although this situation occurred often in the Civil War, a prudent commander
could hardly count on it for victory. Consequently, few commanders chose to
exploit the defensive form of battle if they had the option to attack.
The offensive may have been
the decisive form of battle, but it was very hard to coordinate and even harder
to control. The better generals often tried to attack the enemy's flanks and
rear but seldom achieved success because of the difficulty involved. Not only
did the commander have to identify the enemy's flank or rear correctly, but also
he had to move his force into position to attack and then do so in conjunction
with attacks made by other friendly units. (For the procedure involved in moving
a regiment into line of battle from march column, see figure 1.) Command and
control of the type required to conduct these attacks was quite beyond the
ability of most Civil War commanders. Therefore, Civil War armies repeatedly
attacked each other frontally, with resulting high casualties because that was
the easiest way to conduct offensive operations. When attacking frontally, a
commander had to choose between attacking on a broad front or a narrow front.
Attacking on a broad front rarely succeeded except against weak and scattered
defenders. Attacking on a narrow front promised greater success but required
immediate reinforcement and continued attack to achieve decisive results. As the
war dragged on, attacking on narrow fronts against specific objectives became a
standard tactic and fed the ever-growing casualty lists.
Poor training may have contributed to high casualty rates early in the war, but casualties remained high and even increased long after the armies became experienced. Continued high casualty rates resulted because tactical developments failed to adapt to the new weapons technology. Few commanders understood how the rifle-musket strengthened the tactical defensive. However, some commanders made offensive innovations that met with varying success. When an increase in the speed of the advance did not overcome defending firepower (as Hardee suggested it would), some units tried advancing in more open order. But this sort of formation lacked the appropriate mass to assault and carry prepared positions and created command and control problems beyond the ability of Civil War leaders to resolve. Late in the war, when the difficulty of attacking field fortifications under heavy fire became apparent, other tactical expedients were employed. Attacking solidly entrenched defenders often required whole brigades and divisions moving in dense masses to rapidly cover intervening ground, seize the objective, and prepare for the inevitable counterattack. Seldom successful against alert and prepared defenses, these attacks were generally accompanied by tremendous casualties and foreshadowed the massed infantry assaults of World War I. Sometimes, large formations attempted mass charges over short distances without halting to fire. This tactic enjoyed limited success at Spotsylvania Court House in May 1864. At Spotsylvania, a Union division attacked and captured an exposed portion of the Confederate line. The attack succeeded because the Union troops crossed the intervening ground quickly without artillery preparation and without stopping to fire their rifles. Once inside the Confederate defenses, the Union troops attempted to exploit their success by continuing their advance, but loss of command and control made them little better than a mob. Counterattacking Confederate units, in conventional formations, eventually forced the Federals to relinquish much of the ground gained.
As the war dragged on, tactical maneuver focused more on larger formations-brigade, division, and corps. In most of the major battles fought after 1861, brigades were employed as the primary maneuver formations. But brigade maneuver was at the upper limit of command and control for most Civil War commanders. Brigades might be able to retain coherent formations if the terrain were suitably open, but most often, brigade attacks degenerated into a series of poorly coordinated regimental lunges through broken and wooded terrain. Thus, brigade commanders were often on the main battle line trying to influence regimental fights. Typically, defending brigades stood in line of battle and blazed away at attackers as rapidly as possible. Volley fire usually did not continue beyond the first round. Most of the time, soldiers fired as soon as they were ready, and it was common for two soldiers to work together, one loading while the other fired. Brigades were generally invulnerable to attacks on their front and flanks if units to the left and right held their ground or if reinforcements came up to defeat the threat.
Two or more brigades constituted a division. When a division attacked, its brigades often advanced in sequence, from left to right or vice versa-depending on the terrain, suspected enemy location, and number of brigades available to attack. At times, divisions attacked with two or more brigades leading, followed by one or more brigades ready to reinforce the lead brigades or maneuver to the flanks. Two or more divisions constituted a corps that might conduct an attack as part of a larger plan controlled by the army commander. More often, groups of divisions attacked under the control of a corps-level commander. Division and corps commanders generally took a position to the rear of the main line in order to control the flow of reinforcements into the battle, but they often rode forward into the battle lines to influence the action personally.
Of the three basic branches, cavalry made the greatest adaptation during the war. It learned to use its horses for mobility, then dismount and fight on foot like infantry. Cavalry regained a useful battlefield role by employing this tactic, especially after repeating and breechloading rifles gave it the firepower to contend with enemy infantry. Cavalry also found a role off the battlefield, in long-range raids that interdicted enemy supply lines and diverted enemy troops, in a manner that foreshadowed air interdiction in the twentieth century. The campaign for Vicksburg included two excellent examples of this function. The first of these was a Confederate raid on the Union supply depot at Holly Springs, led by Major General Earl Van Dom in December 1862, that effectively thwarted Grant's first offensive into Mississippi. The second was a Union raid from Tennessee to Baton Rouge, Louisiana, led by Colonel Benjamin H. Grierson, which diverted Confederate attention away from Grant's main effort in April 1863.
In contrast to the cavalry, which reasserted itself as an offensive arm, artillery found that it could best add its firepower to the rifle-musket and tip the balance even more in favor of the tactical defensive, but artillery never regained the importance to offensive maneuver that it held in Mexico. If artillery had developed an indirect firing system, as it did prior to World War I, it might have been able to contribute more to offensive tactics. Still, both sides employed artillery decisively in defensive situations throughout the war.
The most significant
tactical innovation in the Civil War was the widespread use of field
fortifications after armies realized the tactical offensive's heavy cost. It did
not take long for the deadly firepower of the rifle-musket to convince soldiers
to entrench every time they halted. Eventually, armies dug complete trenches
within an hour of halting in a position. Within twenty-four hours, armies could
create defensive works that were nearly impregnable to frontal assaults. In this
respect, this development during the American Civil War was a clear forerunner
of the kind of warfare that came to dominate World War I.
In the Civil War, the tactical defense dominated the tactical offense because assault formations proved inferior to the defender's firepower. The rifle-musket, in its many forms, provided this firepower and caused the following specific alterations in tactics during the war: