The bloodiest battle day of all

In the concrete floor of our garage, just inside the door, is inscribed “September 17, 1912.”

It was obviously scratched into the concrete when it was still wet, before it had hardened. I assume the inscription took place when the floor was poured, not when the garage was built, because the house was constructed in 1901, and the garage (a two-story carriage house) no doubt was built at the same time.

A sharp-eyed friend, a history buff, noted the date, and pointed out that it was the 50th anniversary of the Battle of Antietam, a key event of the Civil War.

This week is the 102nd anniversary of that battle.

Antietam was the single bloodiest battle day in American history.

Casualties totaled 22,717.

The Union sustained 2,108 killed, 9,540 wounded and 753 missing and captured. They added up to 12,401.

The Confederacy had 10,316 casualties, including 1,546 killed, 7,752 wounded and 1,018 missing and captured.

That’s in just one day.

Over 12,000 casualties occurred before noon.

Antietam Creek, near Sharpsburg, Md., lies northwest of Washington, D.C. The Southern commander, Gen. Robert E. Lee, had invaded Maryland, a Northern state, after significant Confederate victories in the opening months of the Civil War. He hoped to use the Southern momentum to occupy Maryland and Kentucky, and maybe persuade them to join the Confederacy.

Lee knew that the South would have trouble winning a drawn-out war against the Union.

He hoped that threatening Washington, just a few dozen miles away, would generate support for a peace agreement in the North that would legalize the Confederacy’s secession. That would be much more likely in 1862 than later in a bruising war.

President Lincoln had named Gen. George McClellan the commander of Union forces. McClellan was very popular with his own men, but his military style was frustratingly deliberate. He chronically failed to press ahead in crucial situations where he held the military advantage.

The Battle of Antietam was one of those situations.

McClellan, commanding 75,500 men, had moved west into Maryland to engage Lee’s 38,000 troops. After two weeks of skirmishes, the armies had drawn up battle lines near Sharpsburg.

At that point, a huge gift fell into McClellan’s hands.

A couple of his enlisted men found a clutch of three cigars wrapped with a sheet of paper. The sheet turned out to be detailed plans and maps, in Lee’s own handwriting, laying out the Southern general’s tactical intentions.

The key piece of information on the sheet was that Lee had sent a significant part of his army to capture the Union arsenal and fort at Harper’s Ferry a few miles to the west.

That knowledge that Lee had divided his forces gave McClellan the opportunity to attack Lee’s depleted brigades, with a major victory for the North a likely possibility.

But McClellan waited 18 hours before finally engaging the enemy. The delay gave the western branch of Lee’s army enough time to capture Harper’s Ferry and rush back to the battle at Antietam Creek, resulting in an indecisive outcome for both sides.

Antietam was fought out in a cornfield and in the surrounding woods. On Sept. 17, the armies charged and countercharged through the cornfield, which changed hands 15 times that day.

An example of the battle’s ferocity took place along a sunken road that had been worn down by wagon traffic, providing a natural trench.

Southern troops took up positions in the road, which came to be known as Bloody Lane. As McClellan’s troops charged, they were mowed down by the Confederate riflemen.

But eventually the Northerners pushed to the top of a nearby knoll which commanded a view of the length of the trench, and opened fire. One Northern soldier said it was like shooting sheep in a pen.

Casualties along the half-mile of Bloody Lane alone totaled 5,600 — 3,000 from the North, 2,600 from the South.

At the end of the day, the North had sustained a few more casualties than the South, but proportionally, the South’s losses were greater. Lee realized that his strategy of pressuring the Union, politically and militarily, had failed, and he left the field and retreated south into Virginia.

McClellan failed to follow up his advantage, infuriating Lincoln, who relieved the dilatory general of his command a few days later.

But Lee’s retreat provided Lincoln with the political opportunity he had been waiting for. Lincoln declared Antietam to be a Northern victory, and five days later, on Sept. 22, he issued the Emancipation Proclamation, which declared that slaves in states “in rebellion against the United States” were now free.

The Emancipation Proclamation, which took effect Jan. 1, 1863, was a military act. It sought to disrupt the South, thereby making Confederate war efforts more difficult.

The significance of Antietam, in addition to the terrible slaughter, was its success in reducing Northern “Peace Democrats” political support, making the Emancipation Proclamation possible.

Antietam was not the most deadly day in American history.

The Galveston hurricane of 1900 killed an estimated 8,000, surpassing the actual deaths at Antietam.

And the Battle of Gettysburg surpassed it in casualties with a total of more than 46,000, but Gettysburg took place over a three-day period.

Antietam gave proof that neither the North nor the South would settle for less than its own ultimate goal.

For the North, it was preservation of the nation. For the South, it was creation of a new nation.

The war would drag on for 2½ long and devastating years before the outcome was decided.