“Lee took longer to learn from his experience that the frontal assault contributed only to attrition without victory than any other field commander in the Civil War.”[i]
Edward Hagerman covers in detail the practices of the Federal and Confederate armies as it relates to entrenchment. McClellan and his successors employed it masterfully. Lee and his generals came to the practice slowly. Hagerman suggests that the reason may have been that, unlike McClellan, Lee lacked a peer group from the Corps of Engineers in the Army of Northern Virginia. [ii] Lee also graduated from West Point before Dennis Mahan (see post here) arrived to instruct cadets on the benefits and “how to” of entrenchment.
An example, despite having the time and equipment to entrench at Antietam (see photo below), Lee did not. According to Hagerman, “his failure to do so suggests that he may have identified with an extreme tendency in American tactical thought opposing all fortifications on the open field of battle, on the grounds that they made green volunteer troops overcautious and destroyed discipline and the will to fight.” [iii]
Burnside Bridge (below) taken from the Confederate viewpoint on the
west side of Antietam Creek looking east.
Likewise at the Battle of Fredericksburg, where Lee assumed “a tactical defense where doctrine called for fortification of his front,” Lee again failed to entrench. “He had his troops construct only a few minor earthworks at scattered positions. This despite Antietam and despite the fact that the rifled musket, with its greatly increased range and accuracy, was now in general use in the eastern theater.” [iv]
Longstreet (above) finally broke the tactical pattern, not Lee.
“Although he occupied one of the strongest natural positions in the Confederate line, Longstreet ordered ditches, stone walls, and railroad cuts occupied and strengthened with rifle tranches and abatis. The Federal assaults against his positions on Marye’s Heights never got within a hundred yards of the stone wall. Behind the wall were four lines of infantry armed with rifled muskets, supported by sharpshooters in rifle trench, and entrenched artillery that directly covered and enfiladed the wall from the two terraces that rose behind it. Their fire cost the Union troops 3,500 dead to their own loses of 800 men.” [v]
Watching the battle with Longstreet, Lee (finally) ordered fatigue parties to entrench the heights as soon as the fighting stopped. [vi]
————
[i, ii] Edward Hagerman, The American Civil War and the Origins of Modern Warfare: Ideas, Organization, and Field Command (Bloomington: Indiana University Press, 1988), 123.
[iii] Ibid., 116.
[iv, v, vi] Ibid., 122
ve arrived in “Studies in U.S. Military History” (see course information 
nnibal’s army through small engagements and cut off their supply lines but avoided getting pulled into a decisive battle. Needless to say, the strategy requires time to succeed. Because of this, it also requires the support of the governing powers on the side that adopts it because there is no decisive showdown event. In Fabius Maximus’ case, the Romans politicians listened to his detractors (peer commanders) and replaced him with men who would confront Hannibal head on. They were resoundingly defeated at the 
came from Nathaniel Greene.
Continental Army, American officers made a concerted effort to pattern themselves after their British peers. A rather startling example… Commander-in-Chief 
