McClernand was a fairly typical pro-Union anti-abolitionist Democrat. This gave him access to a very different constituency in the North West to Lincoln. At the outbreak of the civil war in 1861, McClernand resigned from Congress to raise a brigade of volunteers. He was commissioned a brigadier general of volunteers on 17 May 1861 for largely political reasons – Lincoln wanted to maintain as wide a base of support for the war as possible, and appointing pro-war Democrats to military command was just one of the methods he used.
For most of his military career, McClernand served under U.S. Grant. He was present at the Battle of Belmont as Grant’s second in command. He commanded the First Division of Grant’s army during the attacks on Fort Henry and Fort Donelson. At Fort Donelson (12-16 February 1862) his division suffered the brunt of an attempted Confederate breakout, and had to retreat for two miles before reinforcements arrived from Lew Wallace’s division. Grant was not initially present on the battlefield, and his standing orders had made it much harder for McClernand to receive reinforcements. After the battle he was promoted to Major-General of Volunteers (21 March 1862) as a reward for his efforts.
McClernand’s division was one of the hardest pressed on the first day at Shiloh (6-7 April 1862). It was camped next to Sherman’s division, and McClernand was later to acknowledge how valuable Sherman’s presence had been. McClernand’s corps lost 285 killed, 1370 wounded and 85 missing, compared to Sherman’s 323 dead, 1249 wounded and 299 missing. Between them they accounted for close to a third of the Union losses during the two days of fighting.
It was now that his political manoeuvring began to anger his colleagues. In October 1862, McClernand was granted a leave of absence, and used it to travel to Washington to agitate for a senior command. He eventually succeeded in persuading Lincoln that he could revive enthusiasm for the war in the North West, and raise a new army that could capture the Confederate stronghold at Vicksburg. General Halleck had dispersed the huge army assembled after victory at Shiloh, and Grant was unable to make any significant progress towards capturing this key Confederate stronghold – one of the few remaining blockages to Union control of the Mississippi River.
On 21 October McClernand gained his wish. Secretary of War Stanton gave him the authority to raise troops in Indiana, Illinois and Iowa. Once he had filled Grant’s needs for replacements, McClernand was to command an expedition against Vicksburg. In this first set of orders, only Halleck as General-in-Chief retained any control over McClernand and his expedition.
This state of affairs did not last for long. Neither Grant nor Halleck wanted to have an independent command operating outside the chain of command. By December, Halleck had managed to reduce McClernand’s authority by reducing him to command of one of two army corps to be organised out of his army (the other to go to Sherman). McClernand protested, but he was still senior to Sherman, and still had command of the expedition (under Grant), if he arrived in time.
He didn’t. Sherman was sent to Memphis with orders to move south down the Mississippi as soon as possible. Meanwhile, Grant’s message to McClernand was delayed by Confederate attacks, and when McClernand reached Memphis on 28 December he found that Sherman had left eight days earlier. However, this turned out to be something of a blessing in disguise. Grant’s part of the proposed two pronged attack on Vicksburg had to be abandoned after more Confederate attacks cut his supply lines. The news did not reach Sherman in time to prevent him attempting to attack Vicksburg from the north (Chickasaw Bluff, 29 December 1862) and suffering a very heavy defeat in the process.
Sherman withdrew to Milliken’s Bend, just upstream from Vicksburg. There McClernand finally joined the army, taking command. However, he was now without a plan. Sherman was able to persuade him to launch an attack on Arkansas Post (on the Arkansas River), where 5,000 Confederate troops posed a potential threat to Union operations on the Mississippi. The expedition was a success, but led directly to McClernand’s downfall. Before discovering that the expedition had been Sherman’s idea, Grant complained about it to Halleck, who used the expedition to give Grant the authority to replace McClernand or take direct command of the Vicksburg operation. On joining the army, he decided to take personal control himself. McClernand reverted to his previous role as one of Grant’s subordinates, commanding the Thirteenth Corps.
His attitude during the next few months is the main reason for McClernand’s poor reputation. He behaved with palpable resentment towards Grant, may have spread rumours about Grant’s drinking and clearly felt that he should have command of the army. Over the winter of 1863 others may have shared that opinion. Grant made a series of unsuccessful attempts to get south of Vicksburg. Public opinion began to turn against Grant.
However, Grant soon won his reputation back, and in the process was able to remove McClernand from his command. In April 1863 Grant’s fleet ran past the guns of Vicksburg. Grant marched along the west bank of the Mississippi and crossed over onto the east bank south of Vicksburg. In a series of rapid movements he defeated a series of Confederate armies, and settled down to besiege Vicksburg.
At one of these battles McClernand made his most serious mistake as a corps commander. Champion’s Hill (16 May 1863) saw some of the hardest fighting of the campaign. Only one division from McClernand’s corps was engaged, and when Grant informed him of this, instead of advancing to support this division, McClernand ordered it to pull back to his position. Grant cancelled this order, and began to look for a chance to remove McClernand.
It came one month later. At the start of the siege, Grant had launched two direct assaults on the Confederate lines, in the hope that the Confederates were sufficiently demoralised to allow for an easy victory. Although these attacks failed, McClernand issued a congratulatory order to his corps, phrased in a way that greatly annoyed Grant’s other corps commanders (Sherman and McPherson both complained about the order). McClernand’s real problem was that the order had been published in northern newspapers. This was in contravention of both War Department and Grant’s own orders and gave Grant the reason he needed to get rid of McClernand. Two weeks before the fall of Vicksburg he was relieved of command of the Thirteenth Corps, and ordered back to Illinois.
This was not the end of his military career. The following year he was re-appointed to command the Thirteenth Corps, now stationed on the Gulf coast. This was a minor theatre of operations by 1864. McClernand served for most of 1864, before resigning due to ill health in November 1864.
McClernand clearly divided opinions. General Lew Wallace later described him at Fort Donelson as ‘Brave, industrious, methodical and of unquestioned cleverness, he was rapidly acquiring the art of war’. On the other hand his political manoeuvring made him unpopular with many professional officers, and his performance in the field was not always the best, although he does not appear to have committed any really gross blunders, with the possible exception of his behaviour at Champion’s Hill. Very few of the ‘political’ generals were popular with the West Point graduates who made up most of the Federal high command. McClernand’s manoeuvres in Washington at the end of 1862 perhaps help to explain why. After the war, McClernand served as a judge (1870-73), and remained involved in Democratic politics. Somewhat ironically he died in Springfield, Illinois, where Lincoln’s political career had begun.