The Crater was a Confederate victory. Lee held the line. The Union mine had blown a clean breach in his works at dawn, nearly undefended for the crucial first quarter-hour, and the Union army turned that opening into one of its own worst disasters of the war.

The cost was lopsided. The Union lost about 3,800 men: 504 killed, 1,881 wounded, and 1,413 captured or missing. The Confederates lost about 1,500: 361 killed, 727 wounded, 403 captured or missing. The Union lost roughly two and a half times what the Confederates did, the price of an assault that piled into a death-pit instead of driving through it. Of the Union loss, the single heaviest share fell on the Black division that had been the right unit for the job all along.

The breakthrough was real and it was wasted. Cemetery Hill and the road into Petersburg behind it had been there for the taking in the first fifteen minutes, and with them the chance to get behind Lee’s line and into the city that fed Richmond. Instead the siege ground on for eight more months, and Petersburg did not fall until April 1865. The Crater moved nothing on the map.

A court of inquiry followed, and it spread the blame across the men who had failed the soldiers. It censured Burnside (North), Ledlie (North), Ferrero (North), and others. Burnside was relieved of his corps command within weeks, succeeded by Major General John G. Parke (North), and never held a field command again. Ledlie, drunk in a bombproof while his division died in the pit, was finished and resigned his commission early in 1865. Later, a Joint Committee of Congress shifted blame onto Meade (North) for reversing the plan and pulling the trained division from the lead, and partly let Burnside off.

One man came out of it praised. Lieutenant Colonel Henry Pleasants (North), the engineer of the mine, had no part in the failed assault. He was brevetted brigadier general, cited explicitly for the tunnel his coal miners had dug. The dig was a triumph of the ranks, ordinary men solving an impossible engineering problem with improvised tools and a furnace for a fan. The assault was a failure of the generals above them, and a moral catastrophe besides: the one trained division pulled from the lead to manage how its deaths would look, then spent anyway, then murdered after surrender. The mine remains one of the most remarkable feats of the war. What was built on top of it remains one of its worst.