I'll put forward three theories:
1. XI corps low morale
2. poor selection of positions for union right flank
3. the union line on day one was over-extended
Number 3 might require some explanation. Compare the number of men per mile for the union line on day one versus day three. (The day three line held, the day one line collapsed.)
Day one: 25,535 men/2.07 mile line = 12,335 men/mile
Day three: 85,500 men/2.87 mile line = 29,791 men/mile
IOW, the day three line was better than twice as "dense" (troops/mile). My numbers are not professional, I admit. Details below:
I assume the day one line runs from Barlow's Knoll to the N end of Oak Ridge, then to the Hagerstown Rd where it crosses McPherson ridge. I make that 2.07 miles.
I assume the day three line runs from Culps Hill to Cemetery Hill, then to the S end of Little Round Top (Vincent Spur). I make that 2.87 miles.
My day one union troop totals assume Buford's division plus the 1st corps and 11th corps totals listed by Laino in 'Gettysburg Campaign Atlas'.
May day three union troops total is the one given by Coddington in 'The Gettysburg Campaign'. (Yes, I'm comparing apples and oranges by using 2 different sources for troop numbers.)
Feel free to substitute your own numbers for mine. My guess is the density of the union line on day three was a bunch higher than day one. It seems the union line on day one was over-extended (in addition to the problems with flanks in the air at Oak Ridge and Barlows Knoll).
And of course, the Army of Northern Virginia had something to do with it. Yes!
1. XI corps low morale
2. poor selection of positions for union right flank
3. the union line on day one was over-extended
Number 3 might require some explanation. Compare the number of men per mile for the union line on day one versus day three. (The day three line held, the day one line collapsed.)
Day one: 25,535 men/2.07 mile line = 12,335 men/mile
Day three: 85,500 men/2.87 mile line = 29,791 men/mile
IOW, the day three line was better than twice as "dense" (troops/mile). My numbers are not professional, I admit. Details below:
I assume the day one line runs from Barlow's Knoll to the N end of Oak Ridge, then to the Hagerstown Rd where it crosses McPherson ridge. I make that 2.07 miles.
I assume the day three line runs from Culps Hill to Cemetery Hill, then to the S end of Little Round Top (Vincent Spur). I make that 2.87 miles.
My day one union troop totals assume Buford's division plus the 1st corps and 11th corps totals listed by Laino in 'Gettysburg Campaign Atlas'.
May day three union troops total is the one given by Coddington in 'The Gettysburg Campaign'. (Yes, I'm comparing apples and oranges by using 2 different sources for troop numbers.)
Feel free to substitute your own numbers for mine. My guess is the density of the union line on day three was a bunch higher than day one. It seems the union line on day one was over-extended (in addition to the problems with flanks in the air at Oak Ridge and Barlows Knoll).
And of course, the Army of Northern Virginia had something to do with it. Yes!