PDA

View Full Version : Why Lee fought at Antietam



londo
05-20-2018, 02:55 PM
Meanings

AOP = Army of the Potomac
ANV = Army of Northern Virginia
HF = Harpers Ferry





This is going to be a short recap why the battle of Antietam was fought. For those of you who are interested.

Prelude to the Battle,

After the battle of 2nd Manassas (Aug 28-30, 1862) the defeated forces of Gen. Popes Army of Virginia and parts of the Army of the Potomac retreated to the Federal capital.
Meanwhile Gen. Lee knew, with the win of the strategic initiative he must keep up the pressure,
to force the Federals to put another Army on the field and do not allow them to reorganize the Army in the first place.

Therefore, Lee planned to invade into Maryland to threaten Pennsylvania, Baltimore and the Federal capital itself and in the end put an unorganised Force into the Field.
On Sep 3, 1862 Lee and his ANV entered Maryland north of Leesburg and headed towards Frederick.
Lee knew of the Garrisons of Martinsburg and Harpers Ferry, but he assumed that with the ANV heading north the Federals would abandon the Garrisons, but they didn’t.


Keep in mind, Lee is an opportunist!


Lee have seen this as an opportunity not as a problem.
He figured that this is a good opportunity to have significant Federal forces defeated-in-detail and furthermore to gather badly needed supply for his campaign.

On Sep 9, Lee came up with his plan.
He divided his Force into 4 groups:

Jackson’s Force had to go north-west over Boonsboro towards Williamsport, then turn south-west towards Martinsburg and overwhelm the Garrison and seize the Federal Depot.
When this objective is archived he’d head south-east to approach HF from the west.
McLaws Force should enter the South Mountains to approach HF from north-northeast
Walkers Force should have cross the Potomac and approach HF from south-east.
meanwhile Lee and Longstreet’s Force would continue to move towards Hagerstown what was supposed to be used as a springboard into Pennsylvania.



Meanwhile on the federal side,

Gen. Pope has been disbanded and Gen. McClellan took command over all Forces around Washington and its fortifications on Sep 2.
He was forced to rebuild a scattered, demoralized and unorganized Army into a working Unit again.
It was not the first time he had to do so. He built up the AOP in the first place.
Back then it took him about 6 months to fulfil.
This time he had less than 10 days while moving his Force towards the ANV!

Just some example to picture this.

Some Officer’s did not know how to bring their Line from Marching Formation into Battle Formation
Not less Soldiers did fire their Weapons in the Antietam battle for the first time.
Many Reinforcements were not battle-ready. Some of them were 2-3 weeks from organisation nor didn’t they ever had training.


Carrying many problems, on Sep 7, McClellan finally gave order to move out.
He moved his force from Washington through Maryland up to Frederick until Sep 12.

Deciding to fight

On Sep 12, Lee’s plan was to capture HF this very day, but the HF Garrison was nowhere near to surrender.
As McClellan reached Frederick on Sep 12, he had no idea what Lee’s plan was.
All sorts of conflicting reports blurred the situation. But on Sep 13, 2 Enlisted men found Lee’s Order 191.
Afterwards pictured as Lee’s battle plan, and in other hands the all-in card to end the war.
Unfortunately, it was nothing close!
It was 4 days old, written on Sep 9. Meanwhile Lee changed orders more than once.
It said nothing of the enemy’s strength nor something of tactical interest for McClellan to fight the battle.
But it said something important. It confirmed that Lee’s Army is all spread out. Suddenly many of these conflicting reports made sense.
To approve his thought, McClellan sent Patrols out.

And on Sep 14, McClellan gave order to attack Lee’s lines at south Mountain. Lee wasn’t aware of this move.
McClellan attacked Turner’s gap/ Fox’s gap at Boonsboro and further south at Crampton’s gap.
As Lee pictured what was going on, he ordered Longstreet’s force all the way down from Hagerstown to Boonsboro.
Longstreet himself ordered almost the whole way to move double quick what ended in the loss of nearly 50% of his force for the upcoming fight.
Arriving at Boonsboro, Longstreet and D.H. Hill picked up Hooker’s I. Corps and Reno’s IX. Corps and forced them to a stand-still.
Further down at Crampton’s gap, Franklin’s VI. Corps and parts of Couch’s IV. Corps smashed through McLaws lines and entered the Valley,
what ended in cutting off Anderson and McLaws Units at the bottom of the Valley.

With significant Units cut off, his Units all spread out and the loss of all key terrain, Lee decided that the Campaign is over and ordered a retreat.


Longstreet and D.H. Hill’s Units were ordered to retreat through Sharpsburg and Shepherdstown.
Jackson were ordered to break up the siege and move up to Shepherdstown to cover the retreat.
Lee tells McLaws that he must find some way to move his Force back to Virginia into safety.

During the retreat Lee studied the maps and figured to retreat all the way west to Shepherdstown
is not in the best interest of McLaws Units.
He changed his mind and cancelled the retreat and ordered to make a stand at Keedysville.
Lee’s plan was to force McClellan to concentrate his Force to the north towards Longstreet to support McLaws in his attempt to reunite with the Main body.

After meeting his Staff and some talks with local people, Lee again changed his mind and decided to build up his defence on the west side of Antietam Creek.
Water body in frond of the lines and better ground to defend.

At the point we’re at now, remember, Lee’s plan is to have a temporary stand to retreat all his Units. He is not there to fight a battle!

September 15, 1862 – the big day

Lee is sitting at a local Farmer's house to share a cup of coffee as he received a Message from Jackson written on the evening Sep. 14.
And the Message says this. Garrison at HF about to surrender, finish off tomorrow.

This Message changed everything for Lee. Remember Lee is an opportunist!
And he figures that he got a chance here.

His key questions are “how aggressive McClellan is today” and “How fast can Jackson, Walker and McLaws move”

To Lee’s advantage has to be said that the first Federal Units not arrived at Antietam creek before afternoon,
so McClellan couldn’t attack Lee at this very day, what he was heavily criticized for in the aftermath.
But he could have crossed Units over the Antietam creek, but unfortunately, he did not.

This led Lee to the assumption that McClellan act like he often does.
Prudently and cautiously and that he can attack Lee’s line on the afternoon Sep 16, at the latest, but that he might not even attack then.
Lee figured that McClellan buys him the time he needs to reassembly his Forces in Maryland.

So, in the night of Sep 15, Lee reversed himself and made the decision to go into a battle here!
Except for some Brigades he already pulled his reserve Artillery and his whole Supply Trains out and had them cross the Potomac.
Lee was ready to go, but he decided to stay and fight a battle.

Orders was given to prepare for battle at Antietam Creek, Jackson, Walker and McLaws had to force March up to Sharpsburg to join the Main Body.

On September 16, a dense fog hung over the battlefield, what left McClellan not being able to pin-point the enemy lines.
After the fog finally lifted orders were given but for some reason the Federal Units delayed on the approach.
Finally late this afternoon Federal Units crossed the Creek and some fire fights occur as a prelude to what would become the bloodiest single day battle of American history on September 17, 1862.


Conclusion: Why did Lee offer battle?


Lee was an opportunist
Retreat would mean the end of the Campaign and loss of the strategic initiative to the Federal Forces
Fighting at Sharpsburg carried great risk but also offers a potential of great possibilities if McClellan could be checked or retreated.
In Lee’s mind the opportunity lies in Maryland and the risk is worth it.
Lee sometimes had a tendency to overreach. by Example here and later on July 3rd, 1863, on the Gettysburg Campaign


References:(Book) "To Antietam Creek: The Maryland Campaign of September 1862" (2012, by D. Scott Hartwig)

Ellowsville
05-21-2018, 04:54 PM
Very Interesting!

126th NY
05-30-2018, 04:44 PM
8757
8758
126th NY
Lee fought at Antietam because he believed the he could beat the union in a decisive battle that could force them into surrender thus winning the war for the Confederacy

McMuffin
05-31-2018, 06:50 PM
8757
8758
126th NY
Lee fought at Antietam because he believed the he could beat the union in a decisive battle that could force them into surrender thus winning the war for the Confederacy

Isn't that why a lot Generals fought?