The lead in the assault was decided by drawing straws. The one division that had spent two weeks rehearsing this exact attack was pulled out of it the day before, and the lead going in first was handed by lot, a literal straw, to the least prepared unit on the field. Who was pulled, and why, is the thread the rest of the battle runs along.

The Union army at Petersburg now included United States Colored Troops, the USCT: regiments of Black soldiers, many of them formerly enslaved, fighting in Union blue against the slave republic that had once owned them. The Confederacy had been built to preserve slavery. Eleven states broke away rather than accept any limit on the enslavement of Black people, and raised their armies to defend it. So when Black men, many of them lately somebody’s legal property, stood in the Union line at Petersburg, the war’s cause was in the ranks, carrying a rifle.

It was that division, the trained one, that Major General Ambrose E. Burnside (North), commander of the Union IX Corps, meant to send in first. A word on how those armies were built, because the next two sections lean on it: a Civil War army nested in tiers. A corps was the largest field formation (tens of thousands of men), a corps held two or three divisions (several thousand men each), a division held brigades, and a brigade held the individual regiments. Burnside’s IX Corps, the corps whose sector this was and whose plan the mine assault was, held four such divisions. For about two weeks, two miles behind the line and out of Confederate sight, one of them, Brigadier General Edward Ferrero’s (North) 4th Division of USCT, roughly 4,300 men, drilled the assault specifically. The plan they learned was the right one: when the salient blew, one brigade would peel left and one right to widen the breach sideways, while the rest rushed around the hole, not into it, and drove for the high ground behind, called Cemetery Hill, and the Jerusalem Plank Road just past it, the road into Petersburg. That high ground was the key. A force on Cemetery Hill would be behind Lee’s whole line and astride the road into the city, and taking Petersburg starves Richmond. They were the one unit on the field prepared for this exact attack.

The day before the assault, they were pulled out of the lead.

Major General George G. Meade (North), who commanded the Army of the Potomac and stood between Grant above him and Burnside’s corps below, ordered Burnside not to lead with the Black division. Burnside protested. Grant, over them both, backed Meade. The reason was not that the USCT were untrained; they were the only trained ones. The reason was optics. The fear was that if the Black soldiers led the charge and the assault failed and they were slaughtered, the army would be accused of having thrown Black men away. Grant later explained the calculation to Congress in his own words: if the Black troops led and were killed, it would then be said that the army had been shoving these people ahead to get killed because it did not care anything about them.

The lives of the Black soldiers were weighed as a problem of political perception, a calculation no white division on that field had to survive, made by the same army that had put them in uniform. They were taken out of the lead not because the plan was bad but because their deaths would look bad. So the lead went instead to the three white divisions, who drew lots, that straw, for it. The straw fell to Brigadier General James H. Ledlie’s (North) 1st Division: untrained for this attack, and led by a man already known to have shirked under fire earlier that June. The unit that knew the plan would stand in reserve. The unit that drew it by chance would go in cold.