Industrial age

The evolution of military strategy continued in the American Civil War (1861–65). The practice of strategy was advanced by generals such as Robert E. Lee, Ulysses S. Grant and William Tecumseh Sherman, all of whom had been influenced by the feats of Napoleon (Thomas "Stonewall" Jackson was said to have carried a book of Napoleon's maxims with him.) However, the adherence to the Napoleonic principles in the face of technological advances such as the long-range infantry breechloader rifles and minie ball guns generally led to disastrous consequences for both the Union and Confederate forces and populace. The time and space in which war was waged changed as well. Railroads enabled swift movement of large forces but the manoeuvring was constrained to narrow, vulnerable corridors. Steam power and ironclads changed transport and combat at sea. Newly invented telegraph enabled more rapid communication between armies and their headquarters capitals. Combat was still usually waged by opposing divisions with skirmish lines on rural battlefields, violent naval engagements by cannon-armed sailing or steam-powered vessels, and assault on military forces defending a town. There was still room for triumphs for the strategy of manoeuvre such as Sherman's March to the Sea in 1864, but these depended upon an enemy's unwillingness to entrench. Towards the end of the war, especially in defense of static targets as in the battles of Cold Harbor and Vicksburg, trenches between both sides grew to a World War I scale. Many of the lessons of the American Civil War were forgotten, when in wars like the Austro-Prussian War or the Franco-Prussian War, manoeuvre won the day. In the period preceding World War I, two of the most influential strategists were the Prussian generals, Helmuth von Moltke and Alfred von Schlieffen. Under Moltke the Prussian army achieved victory in the Austro-Prussian War (1866) and the Franco-Prussian War (1870–71), the latter campaign being widely regarded as a classic example of the conception and execution of military strategy. In addition to exploiting railroads and highways for manoeuvre, Moltke also exploited the telegraph for control of large armies. He recognised the increasing need to delegate control to subordinate commanders and to issue directives rather than specific orders. Moltke is most remembered as a strategist for his belief in the need for flexibility and that no plan, however well prepared, can be guaranteed to survive beyond the first encounter with the enemy. Field Marshal Schlieffen succeeded Moltke and directed German planning in the lead up to World War I. He advocated the "strategy of annihilation" but was faced by a war on two fronts against numerically superior opposition. The strategy he formulated was the Schlieffen Plan, defending in the east while concentrating for a decisive victory in the west, after which the Germans would go on to the offensive in the east. Influenced by Hannibal's success at the Battle of Cannae, Schlieffen planned for a single great battle of encirclement, thereby annihilating his enemy. Another German strategist of the period was Hans Delbruck who expanded on Clausewitz's concept of "limited warfare" to produce a theory on the "strategy of exhaustion". His theory defied popular military thinking of the time, which was strongly in favour of victory in battle, yet World War I would soon demonstrate the flaws of a mindless "strategy of annihilation". At a time when industrialisation was reaping major advances in naval technology, one American strategist, Alfred Thayer Mahan, almost single-handedly brought the field of naval strategy up to date. Influenced by Jomini's principles of strategy, he saw that in the coming wars, where economic strategy could be as important as military strategy, control of the sea granted the power to control the trade and resources needed to wage war. Mahan pushed the concept of the "big navy" and an expansionist view where defence was achieved by controlling the sea approaches rather than fortifying the coast. His theories contributed to the naval arms race between 1898 and 1914.