The whole meaning of Fredericksburg is in the imbalance of the cost.

The Army of the Potomac lost roughly 12,500 to 13,000 men, by the detailed count about 12,653, of whom 1,284 were killed, 9,600 wounded, and the rest captured or missing. They were the men of the day just past: the 918 who lay dead in front of the wall, stripped to the skin in the cold; the Irish Brigade that walked up the slope twelve hundred strong and left more than five hundred on it; Humphreys’s boys sent up with empty rifles to die fifty yards short of a wall nobody touched. Lee’s Army of Northern Virginia lost roughly 5,300 to 6,000, about 5,377 with 608 killed, most of them on the southern front where Meade actually broke through; the men behind the stone wall barely had to bleed at all. Union losses ran something like two to two and a half times the Confederate ones, and almost the entire difference came from one place: the failed assaults on Marye’s Heights cost the Union somewhere in the range of 6,000 to 8,000 casualties against perhaps 1,200 Confederates behind the wall. The North brought the bigger army, outnumbering the South by roughly three to two, something like 114,000 engaged against 72,500, and walked away having lost more than twice as many men, without taking a foot of the ground it attacked.

“It was not a battle, it was a butchery.”

Pennsylvania Governor Andrew Curtin (North), to Lincoln, after going down to the field

Lincoln himself is said to have groaned, “If there is a worse place than hell, I am in it.” The Northern press turned savage, one paper writing that it could “hardly be in human nature for men to show more valor or generals to manifest less judgment.” The disaster, followed weeks later by a humiliating, rain-bogged failed march that the army nicknamed the “Mud March,” finished Burnside; in late January 1863 Lincoln replaced him with Joseph Hooker (North), the rival whose name on the command had been the only thing that pushed Burnside to take the job in the first place.

For all the blood, the battle changed almost nothing on the map, and the man who won it understood that better than anyone. Lee’s lines were exactly where they had been; the Union army had simply gone back across the river it came from. Lee later wrote that “at Fredericksburg we gained a battle,” while his people were elated and he himself was depressed, because “we had really accomplished nothing; we had not gained a foot of ground.” It was a textbook tactical victory that decided no campaign. What it did do was teach, in blood, a lesson the war kept charging more and more to relearn: that entrenched infantry behind a wall, with massed artillery above, could destroy a far larger force sent at it across open ground. Frontal assault into a prepared defense was becoming suicide, and Marye’s Heights became the byword for it.

The meaning of the day is also in who, three weeks down the road, the dead had turned out to be dying for. Fredericksburg was fought in the middle of December 1862, at the lowest point of Northern morale: a futile, lopsided defeat, the bigger army butchered against a wall, the country sick of the war. About three weeks later, on January 1, 1863, the Emancipation Proclamation took effect, and the war’s stated purpose openly became the destruction of slavery in the rebelling states. Some of the same enslaved people who had been crossing the Rappahannock to Union lines around Fredericksburg all year, John Washington’s ten thousand, were now free by law, and the army that had bled in front of the stone wall was now formally an army of liberation, whether the freezing men on that slope had known it or not. Burnside’s men had died, at the war’s bleakest hour, for a cause that within the month became the abolition of slavery, while the army that slaughtered them was defending the slaveholding Confederacy that emancipation was about to threaten.