As I was developing my understanding of this epic clash, I naturally concentrated on the three days of the actual battle. I used to think that Lee lost the battle on the evening of the first day when he initially got a look at the developing defensive line on the contiguous hills emanating from the cemetery; when he decided to stay and fight, his fate was sealed.
But as I went back to my source materials to look at the days prior to the battle. I have changed my opinion. Lee lost the battle, and perhaps even the war, on or about 26 June. This was the day that he sent LTG Ewell’s Corps to Carlisle with MG Early’s division going to York. Early’s route took him through Gettysburg and out the other side but Lee took no measures to occupy the city. Also as we see in Section 23, Stuart’s cavalry should have been there to support the defense of Gettysburg.
In truth, on that day the lead elements of the Army of the Potomac were still far to the south near Frederick, MD. Still more than a day’s march from Gettysburg, but Lee didn’t know that at the time. He was actually leaving Early’s rear unprotected.
Existing correspondence says that Lee was considering an attack on Philadelphia. The Confederate leadership seemed to think that both BALTO and WASHDC were too heavily defended to try to attack directly. The thought was that by first occupying the Pennsylvania State Capitol at Harrisburg then moving to PHILA, they could bring sufficient pressure of Lincoln to bring him to the negotiating table. But there was one major flaw in that plan. There was only one way into Harrisburg from the west, across a bridge high over the Susquehanna River. As soon, as elements of Ewell’s infantry approached to within three miles of that crossing, Ewell received Lee’s dispatch recalling him to Gettysburg. No true attack on the capitol was ever launched.
Meanwhile, Early’s mission was to destroy the rail line that passed through York en route from BALTO to Harrisburg and then to try to capture the bridge at Wrightsville. As Early’s cavalry approached that bridge they found it heavily defended by more local militia and decided not to risk an attack until infantry could support them. It was this bridge at Wrightsville that was burned by the local militia and not the one at Harrisburg. So they withdrew back to York. Based on new information as to the whereabouts of the Army of the Potomac, Lee recalled Ewell and Early to meet him at Gettysburg. LTG A.P. Hill’s Corps was approaching and was to occupy the town on 1 July.
By the 29th, LTG Reynolds’ First Union Corps was at Emmittsburg but had not precisely located the Army of Northern Virginia. That was to be the task of BG Buford’s cavalry on 30 June. So by not leaving any troops to safeguard Gettysburg, Lee allowed Buford to concoct his ambush scheme and start the battle on Union terms.
In hindsight, it seems ludicrous that Lee thought that it would take 2 full divisions to attack Harrisburg. Apparently the larger plan was to have Early cross the Susquehanna at Wrightsville and re-join Ewell en route to PHILA. Might Lee have not detached even a brigade from Ewell to provide a screening force at Gettysburg, if only to protect Early’s rear?
Suffice it to say that it seems that Lee made a major blunder by not securing Gettysburg when he had the chance and in doing so left the door open for a Union victory.
In Section 2, I have spoken of the 4Ts of Gettysburg: Tactics, Technology, Timing and Terrain. It is fair to point out here how the terrain features at Gettysburg only worked one way. It is only because Lee was approaching from the west and north that the line of ridges emanating from the town cemetery worked as castle walls to protect the Union troops defending in that direction. The Union Army had three possible routes of approach from the south. Had Lee placed troops to screen and block those routes, the hills in question would have been running parallel to the possible route of advance and would have served no defensive purpose for the Rebels trying to defend against that advance. A battle farther south of the city would have looked entirely different from the actual battle west of the city.
Actually, the heavily wooded and slightly higher ridge that takes its name from the Lutheran Seminary may have been a better gun platform and defensive position that the flatter, balder cemetery line.
A broader perspective on losing the war overall: