Recruiting and Battle of Carthage

Following Lincoln's election, a number of slave states in the American south seceded from the United States and formed the Confederate States of America. The American Civil War began in April 1861 when secessionist forces attacked Fort Sumter.^[10] Tensions grew in Missouri, with Governor Claiborne Fox Jackson mobilizing pro-secession militia to oppose Union Army forces.^[8] Union forces commanded by Brigadier General Nathaniel Lyon dispersed Jackson's militia in the Camp Jackson affair that ended in a bloody riot.^[11] These events led to Slack becoming a secessionist.^[2] After the events at Camp Jackson and the riot, the state legislature formed a new militia organization known as the Missouri State Guard (MSG), which was commanded by Price, who was now a major general. The MSG was composed of nine divisions, each based on a region of the state, with each division commanded by a brigadier general.^[12] The use of divisions was purely geographic, as they were not structured in the traditional military sense. The Ninth Division was never effectively formed due to Union control of the St. Louis region, and the other divisions ranged in size from roughly 400 men to over 2,000.^[2]

Map showing the geographical division of the Missouri State Guard. Slack commanded the   4th Division.

On May 18, Slack was appointed a brigadier general in the MSG by Jackson.^{[8][4][lower-alpha 1]} Slack's command was later designated the Fourth Division,^{[12][14][lower-alpha 2]} and its recruiting area included Chillicothe. From a base along the Chariton River, he recruited and trained soldiers for the MSG,^[8] but he left the recruiting area in June as Union forces were moving into it.^[16] Slack moved his men to the Lexington area, but by that time the MSG had abandoned Jefferson City, the state capital, and had been defeated in the Battle of Boonville.^[8] The defeat at Boonville and loss of the capital forced Price to withdraw the MSG to southern Missouri, where he hoped to cooperate with Confederate forces in Arkansas commanded by Brigadier General Ben McCulloch. Brigadier General James S. Rains, who commanded the Eighth Division of the MSG, and Slack were ordered to organize their MSG units in the Lexington area and then move south.^[18] Slack was a disciplinarian as a commander, and his men showed, in the words of Burchett, "a special affection for him".^[2]

Jackson had gathered together MSG troops near Lamar, and in early July began moving to join Price in southern Missouri.^[11] Late on July 4, Jackson learned that Union forces commanded by Franz Sigel were near Carthage. Jackson formed his troops – the divisions of Slack, Rains, John B. Clark Sr., and Mosby Monroe Parsons – in preparation to defend against an attack.^[19] Slack's command at this time numbered about 1,200 men, and had components of both infantry and cavalry.^[14][20] In the ensuing Battle of Carthage, Jackson remained in the rear and did not exercise overall command, leaving Slack and the other MSG commanders to operate largely independently.^[21] Sigel attacked the MSG lines but was repulsed and driven back through Carthage itself.^[11] During the fighting at Carthage, Slack's infantry was positioned in the middle of the MSG line, while his cavalry component was detached with other MSG cavalry to operate on the Union flank.^[14] Slack's infantry was most heavily engaged during the later stages of the battle, when the retreating Union soldiers were being pursued near the town.^[22]

Wilson's Creek

The MSG then gathered at Cowskin Prairie in McDonald County, but it moved to Cassville to unite with McCulloch's command. The two forces combined in late July. By then, Lyon's Union forces had occupied Springfield.^[23] Price agreed to allow McCulloch to hold overall command with Price as a subordinate, but the relationship between the two officers was rocky.^[24] In early August, the combined forces of McCulloch and Price had begun an advance towards Springfield and encamped along Wilsons Creek on August 7.^[14] Late on August 9, Slack and several other officers supported Price in pushing McCulloch to order an attack against Springfield, which was scheduled to begin the next morning.^[25] However, Lyon struck the Confederate camp in a surprise attack on the morning of August 10, bringing on the Battle of Wilson's Creek.^[14] An acoustic shadow prevented Confederate troops from hearing the firing at the beginning of the battle, and Slack's cavalry component was surprised to encounter Lyon's troops. Slack's cavalry, under the command of Colonel Benjamin A. Rives, made a brief stand that allowed Confederate troops elsewhere time to reorganize, but was driven back.^[26] Slack quickly deployed his infantry into line next to some other Confederate cavalry to face the Union troops.^[27] This deployment gave Price time to deploy other units into line.^[14] This infantry was later engaged in assaulting a position that Union troops had taken up on a prominence known as Bloody Hill, at one point holding the right of the Confederate line.^[28] Three Confederate assaults were repulsed between 7:50 am and 11:00 am, but the Union troops withdrew from the field, with Lyon dead, a Union flanking attack repulsed, and ammunition running low.^[29]

McCulloch's post-battle report praised Slack,^[30] although the latter suffered a bad hip wound while leading an assault.^[14][31] Because of his wound, Slack missed the campaign associated with the Siege of Lexington,^[32] but he was able to resume command on October 11.^[33] In November, a portion of the Missouri state government voted to secede, creating the Confederate government of Missouri, which functioned as a government-in-exile. It is most likely that this portion of the legislature lacked a proper quorum to declare such an action. While the Confederates recognized this government, the United States government recognized the Provisional Government of Missouri, which had been formed several months earlier by the majority of an earlier constitutional convention and had declared the prior elected offices to be vacant.^[34] Many members of the MSG formally joined the Confederate army,^[33] including Slack. Price gave Slack a commission as a colonel in the Confederate army, although Price may not have had authorization to do this.^[32] On January 23, 1862,^[33] after the Confederate Army of the West was formed, Slack was given command of the 2nd Missouri Brigade, a roughly 1,100-man organization that included both Confederate and MSG troops.^[32]

Pea Ridge and death

In January 1862, Price abandoned Missouri and fell back into Arkansas, having been pressured by Union forces commanded by Brigadier General Samuel R. Curtis. Major General Earl Van Dorn was placed in command of Confederate forces in the Trans-Mississippi, and he began a campaign to retake Missouri. Van Dorn sent his army on a hard march to reach the rear of Curtis's position, but the Union commander was able to redeploy his forces to meet the attack, bringing on the Battle of Pea Ridge on March 7.^[35] Advancing that morning, Slack's brigade held the right of Price's forward line.^[36] After repulsing a Union cavalry regiment, Slack's men encountered a stronger Union line which was in the process of deploying, resulting in a brief clash of skirmishers during which time Slack was shot.^[37]

The Fayetteville Confederate Cemetery, where Slack is buried

Confederate Colonel Thomas H. Rosser stated that the bullet hit Slack in the hip, taking a downward path to exit his body,^[38] while another of Slack's soldiers later wrote that the bullet had deflected off of a tree limb and then struck Slack in the groin. Partially paralyzed by the wound, Slack was removed from the field.^[39] The wound was very close to where he had been injured at Wilson's Creek. Initially transported to a private home, east of the field, he was moved to another location 7 miles (11 km) to the east to avoid capture by Union forces.^[31] The wound became infected after the move, and he died on March 21.^[39] The Confederate government promoted Slack to brigadier general in the Confederate army on April 17,^[4] with the promotion to date from April 12 for seniority purposes.^[17] It is possible that news of his death had not reached the Confederate States Senate. The historian Ezra J. Warner writes that Slack was buried "in the yard" at the place where he died,^[4] while Prushankin states that he was buried in the Roller Ridge Cemetery.^[40] Slack was reburied on May 27, 1880, in the Fayetteville Confederate Cemetery. In 1887, a memorial was installed at the Pea Ridge battlefield to honor the Confederate soldiers killed there. Three Confederate generals who died as a result of the battle were named on the memorial: Slack, McCulloch, and James M. McIntosh.^[38]

The historians William L. Shea and Earl J. Hess report that Slack was competent and popular, but had a tendency to be reckless when it came to his personal safety.^[41] After Pea Ridge, Price wrote that Slack was one of his "best and bravest officers". According to Rosser, Slack's men were "devotedly attached to him" and that he was a "model of soldierly bearing". Prushankin writes that Confederate veterans generally viewed Slack as "a person of integrity and courage", and states that he views his primary service to the Confederacy as having been his "ability to inspire and motivate his men".^[40] Burchett describes Slack as "of much more than ordinary ability, cool and clearheaded, and a model of soldierly bearing".^[2]