President McKinley: Architect of the American Century
By Robert W. Merry 

The Forge of War,  pp.25-26

“[McKinley] displayed more than executive ability on September 17th,  the single bloodiest day in American military history, when Lee and McClellan’s armies came together at Antietam Creek near Sharpsburg, Maryland. During the preceding days McClellan had enjoyed partial success in a number of smaller engagements, and now he launched an attack designed to cut off Lee’s escape route.  The battle began at dawn, described by McKinley later as “a lovely September day - an ideal Sunday morning. The fighting raged all day and into the night. Early that morning, the brigade of Colonel Eliakim Parker Scammon, including the Twenty-third Ohio, had taken an important bridge across Antietam creek but later found itself pinned down on the far side of the creek.  Worse, the men had begun the battle without breakfast asb had no access to food or water throughout the day. Famished and thirsty by mid-afternoon, the troops found their fighting ability waning ominously

When Commissary Sergeant McKinley, posted two miles behind the lines, heard of a brigade’s plight, he resolved to get sustenance to the beleaguered unit. He recruited a number of battle stragglers to help him load a wagon with provisions, including cooked meats, pork, and beans, hardtack crackers, and barrels of water and coffee.  He hitched the wagon to two horses and then asked for volunteers to help him get the wagon to Scammon’s brigade. He got one affirmative response, from a young man named John Harvey. The two set off on a narrow road through a thick stretch of forest and into a dangerous clearing in the woods. Twice they encountered Union officers who ordered them back, one saying the enemy position was too well fortified to afford any chance of passage.  But after the officers left, McKinley ignored their orders and kept going. When Scammon’s regiment was almost in sight, Harvey remembered, McKinle “made one more appeal to me to run the blockade, he himself risking his life in taking the lead...and horses going full speed past the blockade.” The back of the wagon was shot away by a cannonball, but within a few minutes they found themselves”safe in the midst of the half-famished regiment.”