I visited Gettysburg Battlefield for 3 days last week. What a Beautifully preserved battlefield! It has the look and feel of a beautiful park. The carnage is forgotten, which would really be too much to experience. But we honor the sacrifice in peace and tranquility that this terrible battle gives us. The statuary is magnificent as well. Not to mention the intricate bas relief on numerous monuments. This inspires in contrast to the cloistered art sheltered in museums away from public life that ofttimes wishes to confuse us and obscure not edify.
One especially interesting site is the Eternal Light Peace memorial on Oak Hill. It's a massive block of granite with a simple bas relief of a pair of female figures representing war and peace with an eagle at their feet on its face of this huge block. These figures enthrall in their simplicity and clarity. The memorial provides a beautiful vista as well. Its a great place to visit even if you don't understand anything about the battle.
Question is what was Lee doing in Pennsylvania? Was it a mistake to invade? The day the battle ended in defeat the fortress at Vicksburg, Mississippi surrendered to Grant who would become Lee's nemesis once Grant came East. Could Vicksburg have been saved? There were regiments from all over the Southern Confederacy defending Lee's Virginia in this invasion. The fall of Vicksburg severed the Confederacy and opened the Mississippi. The Midwest, in minor revolt in some segments (There were wide spread Democratic party victories in the Fall Elections of 1862. The opposition was very adverse to the reason the war began to be being carried on: abolition of Slavery not formerly to save the Union. ) in part due to the blockage of the Old Muddy, could once again gain access to the markets in New Orleans. Could a transfer of those troops have saved Vicksburg? Well, the Confederate victory at Chickamagua, GA. in September of 1863 just 2 months later was due in large part to a transfer of Longstreet's corps to General Bragg.
Lee had many reasons for his invasion: to relieve Northern Virginia of another campaign, demonstrate to the North the continued sacrifice needed to defeat the South and persuade peace minded elements to opposition to the War, and most importantly an attempt to destroy the Union army in open battle "in detail" and pounce on the Union army unavoidably stretched out as it attempted to follow and locate the Confederates and protect Washington at the same time. This strategy would permit the Confederates to battle and defeat a smaller portion of an Army that outnumbered Lee's.
The invasion had many problems. Text book military tactics expect that the army on the offense outnumber the defenders ideally by two or three to one. Lee's army was always smaller than the Union. It took troops from other regions of the Southern Confederacy and thus weakened them. It was much easier to defend in this modern war than to attack. Waiting for the Union army to attack and parry their thrusts, would be the safer and more surefire way to fight the North. Nonetheless, Lee was had several victories to his credit and so his strategy was followed.
As the campaign proceeded Lee found that the cavalry didn't provide information about the Union army's whereabouts. The primary reason for cavalry at this time was to shelter the army as it traveled in order to place a fog of ignorance around it and at the same time acquire information about the enemy and its size and position. Stuart, the famed leader of the Confederate cavalry, numbering some thousands mind you, failed utterly in this task on this campaign. Given contradictory orders by Lee, nonetheless Stuart should have realized his main purpose to gather information not simply wreck havoc on the supply lines. Instead he took a weeks tour if you will around the Union army and even "threatened" Washington, D.C. but in fact completely lost touch with the Confederate Army. As a result Lee's army unknowingly bumped into the Union at Gettysburg. The Union army with forced marches was able to gather itself at Gettysburg and sustain the blows from the Confederates. All in all the invasion was one big gamble that failed and yes, maybe it was worth the risk considering the long odds of defeating the industrial North so evidently overpowering in comparison to the agrarian South. But still a failure.
To top it off there is the folly of the attack against fortified positions at Cemetery Ridge on the third day. Known as Pickett's charge, this attack was a foolhardy and tragic undertaking. On the third day of battle Lee sends some 12,000 troops over a mile of open ground after an ineffectual artillery bombardment against the entrenched Union central sector on Cemetery Ridge. This was against the advice of his Senior Lieutenant, Longstreet. Only some 5,500 come back with thousands killed, wounded, captured. Mind you Union General Burnside failed at this tactic at Fredericksburg some six months before but didn't have enough sense to give up until 16 tries against Confederate positions. This charge was a gamble to break the Union in the center. Now at the same time Stuart, was to have threatened the Union rear, fought and was repulsed by the Union cavalry. His defeat was not critical. His role would have been to harass the broken Union elements after Lee breaks the center.
The three day battle was lost on the first day when two Confederate Corps had driven the 1st and the Union retreating through Gettysburg. General Ewell, Second Corps, allowed them to regroup their forces on Cemetery Hill. This is where General Lee missed Stonewall Jackson decisive aggressiveness, who was killed at Chancellorsville some two months before. Lee's orders to Ewell, leaving his Lieutenant leeway (no pun intended), were to attack the Union forces on Cemetery Hill Southeast of Gettysburg "if practical". Ewell, once again suffering from lack of information due to an absent Cavalry, didn't know if other elements of the Union army lurked close by. These in fact were close in Slocum's 12th corp only six miles south. He, being Regular Army, chose to ignore pleas from the elements under attack (he could hear the sounds of battle), preferring to wait on orders from his superior, General Meade, Commander of the Army of the Potomac, in Taneytown 12 miles away from Gettysburg.
Longstreet, who opposed the invasion in the first place, wanted to restrain from attacking the Union army in prepared positions. His strategy was to try to slide between the Union army Washington. Maybe Lee understood he'd lost his chance to attack the enemy in detail and so his only chance of gaining something out of this campaign was to risk a roll of the dice by trying to break the Union Army at some point. Note the Union army had the benefit of interior lines and could and did move troops back and forth to support areas under attack.
Some days later in retreat from Gettysburg, the Army of Virginia, greatly reduced in size, was held up for days at Williamsport, MD waiting for the Potomac river to recede after heavy rains; their pontoon bridge had been destroyed by Union elements. They of course were retreating back to Virginia. General Meade dallied, fearful, it would seem of attacking entrenched positions, mind you, and the Confederates were allowed to escape back to safety. Here is Lee placing his Army at grave risk but Lee knew Meade and so it wasn't the risk it appears to us, I'm guessing. And my point about defensive war reinforced, while Lee's army was a fraction of the Federal, the risk of attacking entrenched positions seemed too great.
Lee took a gamble he could bring the Union army to a Cannae, a complete defeat. Part of his strategic aim was to enbolden the Peace party in the North with a dramatic defeat of the Union army. Invasion of the North did just the opposite; the Peace party was discredited with the prospect of invasion and further discounted by the defeat and repulse of the the Army of the Potomac. Instead the news the day after the Battle on July 4 was the fall of Vicksburg on the Mississippi; General Grant had forced the surrender of the fortress and its 30,000 troops .
As an offensive weapon the Army of the Potomac was blunted. It would not carry an offensive champaign again. Approximately 30,000 thousand troops were lost to this Southern army. Thousands of the wounded who might have been returned to this Army were left on the battlefield and captured. The officer core was decimated from Regimental officers up to Corp.
Of course a great deal of speculation could be made about what might have happened without the invasion of Pennsylvania. The South was pinned against Richmond the year before by McClellan. Only by gymnastics by Lee was the South able to drive the Federals from Richmond. Taking the risk of placing most of his army against McClellan's right wing and leaving his right flank greatly out numbered was he able to drive McClellan away from the capital, Richmond. McClellan all the while believing he was up against a superior foe and being overly cautious retreated back down the James Peninsula whence he came. There's a good chance that a more determined foe could have captured Richmond; yet, it took Grant nearly a year to do it in 1864-65. And others have questioned the idea of Richmond being made the Capital when Birmingham or some other City in the deep South might have been more defensible. I mention this since loss of Richmond might not have held such importance, leaving troops free to defend elsewhere. Without a major victory before the 1864 elections with the Fall of Atlanta, who knows how much longer the North would have stuck with it. Lincoln could have been voted out and McClellan, his opponent and former General of the Potomac, might have been more amenable to negotiation.