“God only knows what he'll do” - Andrew Curtin, A.K. McClure, and Thaddeus Stevens before Antietam
As Robert E. Lee’s Army of Northern Virginia marched northward out of its namesake commonwealth in September 1862, no one in Pennsylvania or Maryland was aware of the Confederate soldiers’ ultimate desired destination.
Two months earlier, President Abraham Lincoln called for the enlistment of 300,000 new volunteers to fill vacancies in United States armies, and as Rebel troops neared the Mason-Dixon Line, the commander-in-chief urged the usage of all available soldiers to defend against a potential invasion into loyal states.
Alexander McClure, a Chambersburg, Pennsylvania, newsman who served as the nation’s assistant adjutant general that summer, was tasked by Lincoln with garnering a home guard in the south-central region of the Keystone State. Subsequently, “a regiment of volunteers made up almost entirely of the sturdy young men of Franklin and Fulton counties” entered military service, which resulted in an outpouring of nationalism as the young enlistees “started for Harrisburg...in their patriotic work,” McClure wrote. “Speeches were made, flags were waved, tears shed, [and] sorrowing hearts were left behind as the brave men went to their great task, and many to death.”
During the second week of September, from his office in Pennsylvania’s capital city, Gov. Andrew Curtin wired the War Department requesting use of cavalry stationed at the regular Army barracks in nearby Carlisle. That same morning, he communicated with Maj. Gen. George McClellan, whose Union Army of the Potomac pursued the chief Confederate fighting force through Maryland. Curtin related matters as he understood them: The bulk of Lee’s army was outside of Frederick, while Rebel cavalry was spotted nearer to Hagerstown. In response, the governor wished to deploy 400 horse soldiers of his own.
At 10:30 on the night of Sept. 10, McClellan responded to Curtin, verifying his belief “that the information you have received is substantially correct.” The general postulated that Lee’s men were not moving northeast toward Baltimore or Gettysburg as originally suspected, but further to the west. “You should concentrate all the troops you can in the vicinity of Chambersburg, [while] not entirely neglecting Gettysburg,” McClellan instructed Curtin. “I will follow them up as rapidly as possible, and do all I can to check their movements into Pennsylvania.”
“Call out the militia, especially mounted men, and everything in your power to impede the enemy by the action of light troops,” McClellan demanded; “attack them in flank, destroying their trains and any property which must inevitably come into their possession. You may be sure that I will follow them as closely as I can, and fight them whenever I can find them” the general assured the governor. “It is as much my interest as yours to preserve the soil from invasion, or, failing in that, to destroy any army that may have the temerity to attempt it.”
As the geographical emphasis shifted to Chambersburg, affairs forced Assistant Adjutant General McClure to take action. His name found its way into conversations between Curtin and Sec. of War Edwin Stanton as early as Sept. 8, and he had earlier received a directive “to make a draft under the State laws of Pennsylvania,” McClure later recalled. “There was no military force on the border, and not even an officer of the army who had exercised any command of troops,” he maintained.
“I was compelled, therefore, to exercise what little military authority could be enforced under the circumstances,” McClure continued. He would report directly to Governor Curtin, who sent McClure “an army of nearly one hundred” of the Carlisle cavalrymen, “or about one man to each mile of border I had to guard.”
Capt. William Jackson Parker, leader of the small legion, “entered the Confederate lines every night for nearly a week under various disguises, [and] obtained all information possible as to the movements of Lee’s command,” McClure stated. Along with telegrapher William W. Wilson, Parker conveyed to McClure “all movements of the enemy, present and prospective, as far as he had been able to ascertain them.” McClure consequently forwarded any news to Curtin, who redirected it to McClellan.
McClure did not specify which exact date, but later recalled that at some point in mid-September, McClellan telegraphed a memorandum to an unidentified recipient at Chambersburg. In his memoir, McClure pointed out that the note should have been addressed to Brig. Gen. John Reynolds, who had recently been appointed superior officer of the Pennsylvania Militia. (Much to the chagrin of First Corps commander Joseph Hooker, Reynolds was dismissed from command of a “division of Pennsylvania troops of not the best character” at the moment the Army of the Potomac most needed him. On Sept. 12 Hooker opined, “a scared Governor [Curtin] ought not to be permitted to destroy the usefulness of an entire division of the army, on the eve of important operations. It is satisfactory to my mind that the rebels have no more intention of going to Harrisburg than they have of going to heaven. It is only in the United States that atrocities like this are entertained.”)
“‘I am advised that Lee’s probable destination is Pennsylvania, and if he shall advance in that direction, concentrate all your forces and obstruct his march until I can overtake him and give battle,’” McClellan’s telegram disclosed, per McClure’s recollection. “‘The occasion calls for prompt action.’”
“As I was commander and had less than one hundred men, all told, and not twenty of them within fifteen miles of me, the prospect of concentrating my forces and marching out to meet one of Lee’s army corps was not specially enticing,” McClure explained. “I promptly advised Curtin of the situation and the orders I had received from McClellan.”
As McClure notified the governor, one of the most significant figures of his time was present in the Pennsylvania Capitol. “Thaddeus Stevens happened to be in the Executive Chamber when the message was received,” McClure later remembered. Stevens, a boisterous Vermont native who represented Pennsylvania’s 9th congressional district as a radical Republican in the U.S. House of Representatives, had been a Keystone State resident for five decades. Nicknamed the “Great Commoner,” Stevens led the way nationally as an innovator in the realms of education, emancipation, and equal rights—progressive sympathies that stood in stark contrast to George McClellan’s conservative, and oftentimes white supremacist, sensitives.
“McClellan’s order to me to confront one of Lee’s army corps with my force, which did not amount to a corporal’s guard within reach, caused considerable merriment,” McClure sarcastically remarked. “Stevens, who at that time never lost an opportunity to slur McClellan, said: ‘Well, McClure will do something. If he can’t do better, he’ll instruct the tollgate keeper not to permit Lee’s army to pass through; but as to McClellan, God only knows what he’ll do.’”
Despite Stevens’s and McClure’s quips against McClellan’s military prowess (which were undoubtedly inspired partly by political and moral differences), the general eventually reigned victorious after his army drew Lee into battles at the gaps of South Mountain on Sept. 14, and along the banks of Antietam Creek at Sharpsburg on Sept. 17, followed by the Army of Northern Virginia’s withdrawal back across the Potomac River.
Ultimately, no substantial Confederate forces made it into Pennsylvania during what came to be known as the Maryland Campaign. Such would not long be the case, however: One month later, Curtin and McClure had their hands full once more as Rebel cavalry under J.E.B. Stuart raided north into Mercersburg and Chambersburg.
 Damon M. Laabs, “Alexander Kelly McClure,” Pennsylvania State Senate, Spring 2006, https://www.legis.state.pa.us/cfdocs/legis/BiosHistory/MemBio.cfm?ID=5159&body=S; A.K. McClure, Abraham Lincoln and Men of War-Times: Some Personal Recollections of War and Politics during the Lincoln Administration (Philadelphia: The Times Publishing Company, 1892), 365.
 A.G. Curtin to E.M. Stanton, and Curtin to Major-General McClellan, Sept. 9, 1862, in War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies (Washington: Government Printing Office, 1887), series 1, vol. 19, part 2, 228, 229. This source is hereafter referred to as OR.
 McClellan to Curtin, Sept. 10, 1862, in OR, series 1, vol. 19, part 2, 248-249.
 McClure to Curtin, Sept. 7, 1862 (reproduced in Curtin to E.M. Stanton, Sept. 8, 1862), in OR, series 1, vol. 19, part 2, 216; McClure, Abraham Lincoln, 366.
 McClure, Abraham Lincoln, 366.
 McClure, Abraham Lincoln, 367.
 Stevens quoted in McClure, Abraham Lincoln, 367-368.