In the American Civil War (q.v.) (1861-65) the most promi nent tactical lessons were the power of the rifle on the defence, and the ever increasing use of entrenchments to enhance this power. The gun now became definitely the backbone of the de fence, and as the Americans still possessed many smooth-bore guns the discharge of case-shot on the attackers was frequently devastating. Nevertheless the defence was devoid of strategical results, and lack of strategy on the part of the Southern Armies ended the war.
In 1870 the Prussians possessed the superior gun and the French the superior rifle. The French having watched the failure of the Austrian offensives in 1866 determined to base their tactics on the defensive. Moltke, who was a believer in defensive tactics, was thus compelled to assume the offensive. At Spicheren (Aug. 6, 1870) the Prussian tactics were methodical since reinforce ments came forward gradually. At Gravelotte (q.v.) (Aug. 18) the battle was one of manoeuvre prepared by an overwhelming artillery fire. Sedan (q.v.) (Sept. I) was essentially an artillery battle, and the result of a finely executed strategical manoeuvre. In all the battles of this war, whenever the infantry fought in suc cessive efforts, and were predominantly employed, the result was "the complete dissolution of the body of troops engaged, divi sions as well as corps, and extraordinary losses." Breech-loader met breech-loader, and unless the attacker could by artillery fire adequately break down the defender, the attack was repulsed un less it was delivered against a flank.
To all who possessed the slightest tactical perception it was apparent that the leading lesson of this war was that artillery had definitely become the stable element in the fight. Other lessons were : That in certain circumstances the defender can be so com pletely broken by gun fire that the infantry attack can be dis pensed with ; that infantry armed with the breech-loading rifle need pay no longer any attention to cavalry; that, to initiate an attack, all the artillery must be brought into line as soon as possi ble, and must not only crush the enemy's artillery but prepare the infantry advance by a lengthy bombardment. Yet, in spite of this, as the war showed, fronts had become inviolable, for, throughout the war, neither the French nor the Germans succeeded in taking a single position by a frontal attack. The infantry breech-loading
phalanx was unbreakable, and cavalry though they could turn it were incapable of attacking it in flank or rear.
"Troupes de choc," "Masse de manoeuvre" and such like meta physical terms were invented. It was considered that well-led troops must overcome all obstacles. A veritable spell fell not only upon the army of France but on all the armies of Europe.