After Antietam and during what could easily be referred to as a “period of masterful inactivity,” General George McClellan’s large and well supplied Army of the Potomac remained essentially dormant, allowing Robert E. Lee time to recover from his first attempt to invade the American North.
By mid-October 1862 General Josiah Gorgas, the Confederate national government’s chief of ordinance, had armed the South. To do so, Gorgas not only purchased munitions in Europe, but his agents roamed the South, confiscating whiskey stills to provide copper for percussion caps and church bells for the bronze needed for cannon. He encouraged soldiers to scavenge battlefields for weapons; in one year alone 100,000 discarded Union firearms were collected.
Keeping soldiers encamped for extended periods exposed them to numerous camp illnesses. So devastating were these sicknesses that for every soldier that perished in action two died behind the lines from sickness. The most common illness was dysentery, an infectious disease marked by severe diarrhea. One million cases were reported among the two million soldiers of the Union armies; the statistics were as bad or worse for the Confederates.
On October 26, 1862, embarrassed by his army’s inability to stop Stuart’s recent raids and by President Lincoln’s continuing criticism, General George McClellan ordered the Army of the Potomac into the field, crossing the Potomac into Virginia. In Washington, Lincoln immediately wrote McClellan that he “rejoiced” that the Army of the Potomac was moving into Virginia and encouraged McClellan to take the war to Lee’s Army of Northern Virginia.
On Saturday, October 25, 1862, President Abraham Lincoln, annoyed with General George McClellan’s excuses for procrastination after Antietam, wired McClellan, noting “I have just read your dispatch about sore tongued and fatiegued [sic] horses. Will you pardon me for asking what the horses of your army have done since the battle of Antietam that fatigue anything?”
The Battle of Perryville, Tennessee halted the Confederate invasion of Kentucky and forced Bragg’s withdrawal into Tennessee. When Don Carlos Buell failed to pursue Bragg, he was relieved of command on October 24, 1862, and replaced by General William S. Rosecrans. Buell would spend the next year and a half in Indianapolis, in military limbo, hoping that a military commission would exonerate him of blame; he claimed he had not pursued Bragg because he lacked supplies.
Despite Lincoln’s urgings, General George McClellan’s Army remained disengaged with the enemy in mid-October 1862. Lincoln himself calculated that the Army of the Potomac had a total of over 231,000 men, of whom 144,000 plus were fit for duty. The president could not understand McClellan’s procrastination.
On Monday, October 20, 1862 President Abraham Lincoln ordered General John A. McClernand of Illinois, a close personal friend and political ally, to recruit a force from Indiana, Illinois, and Iowa which would conduct operations against Confederate held Vicksburg, Mississippi. Four days earlier General Ulysses Grant had been appointed commander of the Department of Tennessee, which gave Grant command against Vicksburg.
After Don Carlos Buell’s Union forces defeated the Confederates of Braxton Bragg at Perryville, Kentucky on October 8, 1862, Confederate forces abandoned Lexington, Kentucky. On October 16 Union forces occupied the city, with Union Major Charles B. Seidel and his command occupying Ashland. However, two days later on Saturday, October 18, 1862, in a daring daylight exploit General John Hunt Morgan and his Confederate raiders defeated Federal cavalry near Lexington, Kentucky, capturing Union Major Charles B. Seidel and his command.
Federal officials reviewed the work of Major Jonathan Letterman, head of the Army of Potomac’s medical corps, in light of Union casualties suffered at Antietam. General George McClellan had earlier tasked Letterman to improve the efficiency of the Union medical corps. Letterman responded, forming an independent ambulance corps to remove the wounded from the battlefield. Then, at sites off the battlefield a system of triage—determining casualties as lightly wounded, severely wounded, or fatally wounded—would be used.