Let’s say Ewell hadn’t siphoned off some of the artillery and the supply trains were close enough that Longstreet’s barrage kept up as planned. I’ve stood on Cemetery Ridge and that damned cornfield is still a literal mile wide. Could Picket have broken through?
What if Custer had not delayed Stuart? A pincer movement using infantry at the front and cavalry at the rear looks like it would turn the Union lines to chaos. Did Custer win the Battle of Gettysburg?
Even if Longstreet’s barrage kept up as planned, you’re still talking about a 3/4 mile charge over flat, open terrain against an entrenched, covered position. I don’t think there’s any way it could have succeeded.
But if Stuart had disrupted the defense…
ETA: Cavalry, operating as cavalry, like Stuart’s, and not as mounted infantry, can completely freak out infantry, especially if it comes from an unexpected angle.
ETAA: But that field is still awful wide.
No way in hell.
The only rational plan was Longstreet’s request to try to flank to the right, past Little Round Top and around the left flank of the Union forces. If they had done that the second day, the Confederates might have had a chance. But once they were repulsed at the Devil’s Den and the Peach Orchard (props to my greatx4 grand-uncle), the battle was lost. I don’t think a Confederate capture of Little Round Top would have made a difference, either. Pickett’s was doomed from the start.
Where would Stuart have attacked? Against Slocum? Sedgwick? By the third day, the Union forces were too deep for an attack by Stuart to have had any effect on Cemetery Ridge.
I stand in awe of your Confederate War knowledge.
ETAAA: And they did most of it at a walk. Against cannister and massed rifles the last few hundred yards.
Poor bastards. 
Dude, I’m a fucking amateur. Wait until the pros weigh in. 
The noobs have no idea what THOSE GUYS are like! I am a mere spark that started the fire and I’ll stand back while the pros weigh in, though my high-school visit to the diorama at the battlefield first made me ask, “WTF was Stuart doing back there?”
Note: This isn’t trolling. It is sparking a discussion.
Grandpa Simpson Anecdote: We were in the cemetery. One of our chaperones remarked at how large and stately the trees were that stood over the graves. I suggested they were well-fertilized.
Another note: Custer has dogged my footsteps all my life, from when he captured Charlottesville in our sesquicentennial pageant to my visit to the Little Bighorn, where I pronounced words similar to those of anybody there who was familiar with the event, “He was fucked.”
It’s tempting to say that there was no chance, but very unlikely things sometimes happen. By all rights, a true frontal assault on Missionary Ridge should have had no chance to succeed, and wasn’t even contemplated by Union commanders at the time – nonetheless, through its own accidental momentum, the attack routed what should have been an impregnable position. So I suppose it could’ve happened at Gettysburg, if the Confederates caught enough breaks and the Union hierarchy made enough errors. Call it a 5-10% chance.
Agreed that Stuart’s diversion was doomed to irrelevance. By that point the Union forces were, for all intents and purposes, arrayed in a circle – there was no rear for the cavalry to strike.
Roger that. I remember my last visit to Greasy Grass. As we walked the battlefield, I just kept thinking “Moron. Moron. Moron.” Then when we got to the crest of Last Stand Hill, and could see where Gall crossed the river and swept up behind the 7th, the mantra changed to “Poor Sorry Bastards.”
Eldest considered going to the Lutheran college in Gettysburg. I couldn’t get past that being Seminary Ridge.
Totally fucked, and I keep Fox’s archaeological analysis under my pillow.
Okay, it’s been on the floor for a month and I just picked it up today, but still. 
In order for the South to win Gettysburg, Pickett’s Charge can’t happen. A.P. Hill has to realize that he hasn’t actually found the Army of the Potomac, he just found some scouts. He needed to blow right through them, and take the high ground on the first day, before the Army of the Potomac shows up that night. If he does that, it’s a whole different battle. The South is dug in on top of the high ground, and the Yankees have to fight their way up the reverse side of the hill.
One of my ancestors was part of Pickett’s Charge. He fell at the stone wall just shy of the “High Water Mark”…or so the family story goes.
My aforementioned grand-uncle: Private Moses Potter, Company D, 3rd South Carolina Volunteer Infantry Battalion, Kershaw’s Brigade, McLaw’s Division, 1st Corps (Longstreet), Army of Northern Virginia (Robert E. By God Lee). Right in the thick of it at the Peach Orchard July 2nd. The unit suffered horrendous casualties, but the Union III Corps was shredded.
The whole battle changed when Reynolds held Day One. Just long enough.
Reynolds, for all intents and purposes, selected the battleground, but got killed almost immediately. Yes, the area around Gettysburg is eminently defensible if one holds the considerable high ground, as the Federals did for the most part, but was it a conscious choice or just where he happened to be? And, though Abner Doubleday has received far more than his share of glory, he did take over for Reynolds. And as Buford first delayed Ewell, which should give him some credit.
And I know that Ken Burns has a total man-crush on Chamberlain, but the Federal forces on Little Round Top did prevent the rebels from gaining even that bit of favorable terrain.
The whole battle started as a meeting engagement that neither side wanted. Because of that, there was confusion and disorder. 20/20 hindsight shows that Longstreet was right, and the Confederates should have swung around to the right and cut off the Union forces. Major credit on the Union side has to go to Hancock, who instantly recognized the strength of his defensive position and made the most of it. If, if, if…
If Hill’s forces had charged though the initial Union positions…
If Ewell hadn’t been confused by Lee’s “if practicable” …
Hell, if Ewell had done his job…
If Stuart had actually done his, and screened the ANV, rather than haring off to gather glory…
See, that’s what I meant. Custer was not brilliant and, had Stuart been where he BELONGED…
Who was it who said that, had Southerners not read “Waverly,” the war might never had taken place?
Burns undoubtedly got that crush from Michael Shaara, whose The Killer Angels is really quite a remarkable book. Shaara was totally besotted with Chamberlain.
Not without reason: Chamberlain’s heroism on the second day, and its importance, are quite real - and it’s just one piece of the arc of an exceedingly remarkable life.
But Bruce Catton, in his Army of the Potomac trilogy, gives a much more measured account of Chamberlain’s importance in the overall action of the second day, describes no less than a half dozen separate instances where the Confederates came scarily close to turning or breaking through the Union line; Chamberlain and the 20th Maine stopped only one of these. It took a great deal of heroism under fire to hold the Union line during that long afternoon and evening.
Not a civil war buff, so perhaps this is a foolish question - but did no one consider, well, running? Perhaps in some sort of crouch? Dodging from side to side a bit?