Renowned flag expert Howard Madaus and Dr. Richard Zeitlin, Director of the Wisconsin Veterans Museum, give an excellent introduction to the role of battle flags during the Civil War:
During the American Civil War, as in earlier conflicts, the flags of a combat unit (its "colors") held a special significance. They had a spiritual value; they embodied the very "soul" of the unit. W. H. Druen of Rockville, Wisconsin, witnessed the attachment the men had to their colors when he wrote home on August 1, 1861. 3
We are the color company of the Sixth Regiment, and carry the Regimental colors; and I feel safe in saying in behalf Company 'C' that the splendid flag entrusted to our care, shall not be dishonored by an act of ours. We shall bring it back unsullied by traitors' hands.
Indeed, the loss of its colors in combat could seriously jeopardize the morale of that unit. After the regimental color of the Sixth Wisconsin briefly fell into the hands of the Eightieth New York at the battle of Antietam, Lieutenant-Colonel Edward S. Bragg felt it necessary to explain... 4
that the regiment conducted itself during the fight so as to fully sustain its previous reputation; that it did not abandon its colors on the field; that every color-bearer and every member of the guard was disabled and compelled to leave; that the State color fell into other keeping, temporarily, in rear of the regiment, because its bearer had fallen; but it was immediately reclaimed, and under its folds, few but undaunted, the regiment rallied to the support of the battery. The color lance of the National color is pierced with five balls, and both colors bear multitudes of testimony that they were in the thickest of the fight.
But beyond these transcendental factors, flags served at least three practical purposes on the nineteenth-century battlefield.
At the beginning of the Civil War, colorful uniforms were adopted or adapted from pre-war militia service by the belligerents of both sides to enhance unit morale or state pride. Such uniforms were not always conducive to distinguishing friend from foe. Indeed, the Second Wisconsin, outfitted by Wisconsin in gray uniforms, found itself under fire from both friend and foe during the first battle of Bull Run! The thick gray-white smoke that clung near the ground on battlefields of the black-powder era further complicated the problem. In such circumstances, flags were often the only means of distinguishing the identity of the combatants.
Unit flags also served as the focal point for maintaining alignment within the unit during an era when linear tactics predominated. The single-shot, muzzle-loading musket dictated that infantry fight in closely formed, standing lines of battle to achieve effective concentration of fire. In spite of the revolution caused by the adoption of the rifle-musket, which increased the effective range of a regiment from seventy-five yards to well over 250 yards, the battles of 1861 and early 1862 were largely fought with the smoothbore muskets of earlier periods, and officers were trained to handle their men accordingly. Volley fire (necessitated by the inherent inaccuracy of the smoothbore musket) demanded strict attention to proper alignment of all segments of a military unit, lest a portion of the unit's fire fall harmlessly short. The unit's colors, situated in the center of the firing line, provided the focal point by which company commanders aligned their formations within the unit before firing. "Guiding upon the colors" remained an important command even after the rifle-musket drastically altered the necessity for strict lineal alignment.
Lastly, flags served as the focus for leading an assault or for rallying a broken unit. Where the colors went, the men followed. Describing his part at Antietam after he had recovered the unit's state flag, Major Rufus R. Dawes of the Sixth Wisconsin recollected:5
At the bottom of the hill I took the blue color of the State of Wisconsin, and waving it, called a rally of Wisconsin men. Two hundred men gathered around the flag of the Badger state. . . . I commanded 'Right face, forward march,' and started head with the colors in my hand into the open field, the men following.
And, where the colors went, men usually died.
Because the colors drew an inordinate share of enemy fire and were the object of capture, the color-party of the period was large and more than ceremonial. The national color was carried by a sergeant, while the regimental or state color was carried by a corporal. Anywhere from four to seven other corporals were selected to form the color-guard6 whose sole duty in combat consisted of protecting the unit's flags. Only after the flag was removed from a functional combat role did military tacticians reduce the size of the color-guard. (Madaus and Zeitlin 5-6)
Madaus, Howard Michael and Richard H. Zeitlin. The Flags of the Iron Brigade. Madison: 1997.
3 CWV, Vol 1 pp.238-240
4 U.S. War Department, The War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies (Washington 1880-1901), Series 1, Vol. 19, Pt. 1, P. 255
5 Rufus R. Dawes, Service with the Sixth Wisconsin Volunteers (Marietta, Ohio, 1890), 91.
6 U.S. War Department, U.S. Infantry Tactics, for the Instruction, Exercise, and Maneuvers of the United States Infantry, Including Infantry of the Line, Light Infantry, and Riflemen... (Philadelphia, 1861), 10-11.