The 1962 Stinson Study: Second Entry

Fifty years ago, National Park Service historian Dwight E. Stinson, Jr. set out to “present a definitive study of the operations of Sedgwick’s Division at the Battle of Antietam.” Part III: Analysis was posted earlier, what follows below is Part III: Sumner's Dispersal of Force.

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"Part III-Sumner's Dispersal of Force

Francis Winthrop Palfrey
Detail from Carte de Visite
Massachusetts Historical
Society.

As in most combat conditions, two situations existed in the zone toward which the II Corps was marching. One was the clear, uncluttered, and correct dispositions shown on the battle map and including such pertinent information as the enemy order of battle. The other was the situation as it appeared to the commander in the field, in this case General Sumner, complete with smoke, confusion, topographic obstructions, conflicting reports, and above all the knowledge that it was his responsibility to bring his men into action agains an enemy of unknown strength in an undetermined position.

Critics are prone to pass judgement on the basis of the former situation with little, if any, reference to the latter. It is safe to say that if Sumner had had the same amount of time to interpret it, he too would have made the correct decisions. The analyst must attempt to correlate the true situation with the facts known or available to Sumner before deciding if his attack was "madness"as Palfrey[1] has stated or if it was the most logical move under the circumstances.

Prior to 8:30 the Confederate main line of resistance on the northern sector of the battlefield was roughly West-Woods-East-Woods-Mumman House. Greene's breakthrough in the East Woods and advance to the Mumma Farm cleared the area north of the Dunker Church and east of the Pike, thereby shifting the Confederate line to one running generally north from the Church through the West Woods.[2]

Brig. Gen. George Sears Greene, XII Corps

South of the Church the line remained unchanged except that the Sunken Road position became an angle and the only part of the entire Confederate main line of resistance still fronting north. All of this took place less than half an hour before Sumner reached the East Woods. It had the effect of bringing his line of march across, rather than on, the axis of the earlier Federal attacks. The shift also created a gap between the divisions of the XII Corps (Williams and Greene) which would have a direct adverse bearing upon Sedgwick and the entire II Corps.

The sudden collapse of the Confederate line in the Cornfield area found Williams' Division in poor condition to follow-up. It had relieved the I Corps some time before and had suffered heavily in the sustained combat that preceded Greene's breakthrough.

The greater part of Crawford's Brigade was in the rear trying to regroup its depleted units.[3] Only three regiments of the entire division were even in proper position for pursuit [4] and their ranks were greatly reduced. Nevertheless, the three regiments were advancing into the Cornfield when sumner's advance was announced on the filed. The colonel of the 27th Indiana reported:

'They [the Confederates] broke and fled, in utter confusion, into a piece of woods on the right. We were then ordered to fix bayonets and advance, which was promptly done...We had advanced over the larger portion of [the Cornfield] when we were ordered to halt. I soon discovered that General Sumner's corps had arrived and were fresh...and the work of dislodging the enemy from the woods, designed for your shattered brigade, had been assigned to them.[5]'

Frank H. Schell's eyewitness rendering of Sumner,
Sedgwick and Staff advancing the division to
the West Woods.

Such was the situation Sumner found on his immediate front which goes a long way toward explaining what motivated his seemingly hasty advance. to express it very simply, the enemy main line was in headlong flight and the only pursuit force was a battered combat team of three regiments. It was the perfect moment for 5,000 fresh men to arrive and the most conservative of commanders would probably have done the same thing Sumner did and that is order the division forward.

But the key to the situation was the location and condition of Greene's Division. This small but organized body was, at the time Sedgwick entered the East Woods, regrouping on the Mumma Farm after its successful attack. It was also awaiting ammunition without which it could not continue its offensive operations.[6] Unfortunately Greene was the only general officer on the field who was aware of these facts. The wounding of Mansfield had left Williams in command of the XII Corps but at the time in question he was occupied in pulling the scattered units of his own division out of Sedgwick's line of advance. It is almost certain that he had no accurate information on Greene's whereabouts and condition.[7] To Sumner, Greene's Division appeared to be nothing more than 'some troops lying down on the left.'[8]

French, under orders to form on Sedgwick's inner flank, had an entirely different view of the situation. His line of march brought him in behind Greene and he could readily see that rather than a few scattered men, Greene commanded a fully organized division. Accordingly, he gave way to the left.[9] This was among the most critical decisions in the Battle of Antietam, for it severed Sedgwick from the rest of the corps and brought on two separate actions neither of which could support the other. Sedgwick attacked almost due west but because of the angle formed by the Sunken Road French, and later Richardson, struck almost due south. It left Sedgwick's flank completely uncovered, a fact unknown to the corps commander because he was with the lead division. This all occurred because Sumner and French interpreted Greene's presence in the opposite manner:

1. If French had seen Green as a small, disorganized body he would have passed over him and remained connected with Sedgwick's left.

2. If Sumner had seen Greene as a division with offensive potential he would have consulted with him probably before moving Sedgwick forward. This might have led to a coordinated movement of three divisions (Sedgwick, Greene, and French). At worst, it might have caused Sumner to wait long enough to ascertain French's position and insure that the two divisions would go in together.

Next post, "Conduct of Attack"

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Dwight E. Stinson, Jr. Operations of Sedgwick's Division. Unpublished, National Park Service Report, 1962. This typescript report is at the Antietam National Battlefield Library and Archives.

Annotations below within quotation marks are from the Stinson report.

[1] "Francis Winthrop Palfrey, The Antietam and Fredericksburg (New York: Charles Scribner’s Sons, 1882)."

[2] Here Stinson cites: "Sunken Road Report, 10. The changed position of the battle lines is also discussed in some detail by General Cox in B&L, II, 645 and may be seen by comparing Cope Maps #7 and 8." Stinson identifies these sources in his bibliography as: Sunken Road Report is Dwight E. Stinson, The Attack on the Sunken Road: Operations of Richardson's and French's Divisions. Unpublished, National Park Service Report, 1961; B&L is R.U. Johnson and C.C. Buell, eds., Battles and Leaders of the Civil War. 4 vols. (New York: The Century Co., 1884-1888); and Cope Maps are Antietam Battlefield Board, Maps of the Battlefield of Antietam. 14 sheets. Surveyed by Lieut. Col. E.B. Cope. Washington: United States War Department, 1904 and Revised 1908.

[3] O.R.., 487 (Knipe). Stinson notes in his bibliography that "All references [to the Official Records] are from Volume XIX, Part I unless otherwise cited. "[References] will be cited O.R. followed by the page number and the name of the person who submitted the report, as follows: O.R., 275 [Sumner]."

[4] "Cope Map #7. The regiments were the 27th Indiana, 2nd Massachusetts, and 3rd Wisconsin all of Gordon/Williams/XII. The three new Pennsylvania regiments of Crawford's Brigade were also on or near the line as was the 13th New Jersey but these units were operating almost on their won."

[5] "O.R., 499 (Colgrove)."

[6] Greene Report, 9. Stinson's Greene Report is to his bibliographic source : "Dwight E. Stinson, Analytical Study of the Operations of Greene's Division. Unpublished, National Park Service Report, 1961."

[7] "Greene Report, 19-21. Carman, 183, claims that Williams rode up to Sumner from the direction of the Mumma House but it is probable that he mean Miller rather than Mumma."

[8] "C.C.W., I, 368 (Sumner)." Stinson's C.C.W. abbreviation is to his bibliographic source which is Thirty-eighth Congress, Report of the Joint Committee on the Conduct of the War. 4 vols. Washington: Government Printing Office, 1865.

[9] "Sunken Road Report, 10."