Petersburg lay open. The eastern wall was gone, the defenders were a thin scattering of exhausted men, and a single hard push the remaining mile into the city in the gathering dark would very likely have ended it: the capture of the rail hub, the unhinging of Richmond, perhaps a war shortened by the better part of a year. The man with the open door in front of him chose not to walk through it.

Brigadier General William F. Smith (North) decided to wait. Rather than press his advantage into Petersburg in the night, he chose to hold what he had taken and resume the attack at dawn. He was tired, his men were tired, the ground ahead was dark and unknown, and a fresh Confederate corps might for all he knew be waiting in it. His caution is understandable. It was also the costliest hesitation of the campaign.

It was made worse by what happened when help arrived. Major General Winfield S. Hancock’s (North) II Corps came up that evening, fresh troops, exactly what was needed to finish the job. But Hancock was uncertain of his orders. In one of the war’s famous administrative failures, he had not been told that Petersburg was the day’s objective at all; the orders that should have made it clear had miscarried, the lost order that haunts every account of this day. Not knowing the situation and arriving on a field someone else had been fighting all day, Hancock, normally one of the most aggressive corps commanders in the army, deferred to Smith’s judgment to wait. And so two Union corps stood in the dark outside a city that was theirs for the taking, and did not take it.

The man on the other side of the line understood how narrow his escape had been. Beauregard (South) later wrote that the city had been within the Federals’ grasp and that they had thrown it away, that only the Union commander’s inability to believe how few men were actually in front of him had saved Petersburg.

“Petersburg at that hour was clearly at the mercy of the Federal commander, who had all but captured it.”

General P.G.T. Beauregard (South)

Beauregard did not waste the night the Union had given him. While the Federals slept, he pulled his battered force back a short distance to a new line he entrenched along Harrison’s Creek, just west of the lost Dimmock batteries, and dug in. By the morning of June 16 he had also concentrated reinforcements, the divisions of Robert F. Hoke (South) and Bushrod R. Johnson (South), bringing his strength to roughly 14,000 men. That was still desperately outnumbered: Grant now had something like 50,000 across the field, and arrived in person with Major General Ambrose E. Burnside’s (North) IX Corps. But 14,000 dug-in men is a different thing from 2,200 spread thin, and the difference was twenty-four hours of Union hesitation.

The Union attacked anyway, and the door that had stood wide open the night before was already swinging shut. Hancock’s assault opened around 5:30 that evening. The Confederates fought fiercely, throwing up new breastworks (chest-high dirt walls raised fast) even as breakthroughs tore at their line. Brigadier General Francis C. Barlow’s (North) division took Redans 13, 14, and 15 (a redan being an arrowhead-shaped earthwork, its point aimed out at the enemy) but was driven back out, leaving prisoners behind. In the same fighting Colonel Patrick Kelly (North), commanding the storied Irish Brigade, was killed. The chance to walk through the open door had died with the daylight on June 15. Now the door had to be forced, and forcing it would cost everything that easy push would not have.