Even as Lincoln's multi-front spring offensive, known among many discontent Union soldiers as 'Lincoln's March Madness', seemed to sputter out, there remained an opportunity in the far west to cripple the Confederate war effort. Union forces had seized control of the Mississippi river and vital port of New Orleans, effectively splitting the Confederacy in two. However, the Trans-Mississippi Department remained a relatively large force, and the river required substantial garrisons along its course to avoid being vulnerable to Confederate capture. Guns, food, and supplies still regularly made their way from Texas to the eastern portion of the Confederacy. Further, rebel forces in Arkansas and Oklahoma had made significant progress against their Union counterparts and were in positions to threaten Memphis and Missouri, respectively. Henry W. Halleck had devised a plan that would secure Union control of the Mississippi, fully separate Texas from the rest of the Confederacy, and severely damage the Trans-Mississippi department by taking control of the Red River valley and Shreveport, the city in which it the department was centered.
The plan involved a combined movement from the Department of the Gulf under Nathaniel P. Banks, the Mississippi Flotilla of the US Navy, and a contingent of men from the Department in Arkansas under General Steele. It was intended to take a number of small forts by surprise and trap the small Confederate force in the Red River valley under Richard Taylor, which would then most likely surrender. It began on March 10th as Major General William B. Franklin, commanding the advance divisions of Banks's Army of the Gulf, began his march from southern Louisiana. However, this campaign would quickly begin to fall apart due to miscommunication and poor timing among the three principal Union forces. The Mississippi Flotilla was halted from entering the Red River by Fort de Russy, which could potentially have been caught by surprise by a land force but spotted the flotilla at great distance and quickly prepared their heavy artillery. Meanwhile, Taylor's force, alerted by the failed attempt by the flotilla to break through, quickly made its way south to deal with a potential advance, clashing with Franklin's divisions along a road a small ways south of Marksville. Franklin's force, outnumbered and caught by surprise, was easily repelled, and continued to suffer enormous damage as it retreated to Mansura. Over the next few days, large contingents of cavalry from the District of Texas would arrive to reinforce Taylor's army as it arrived in Simsport (present-day Simmesport). Meanwhile, the badly battered divisions under Franklin were finally re-united with the rest of the Department of the Gulf under Banks, in a position opposite Taylor on the other bank of the Atchafalaya River.
The Union naval flotilla and Department of the Gulf found themselves unable to support one another, seperated by a few dozen miles of land between their positions which neither found themselves capable of advancing from. Meanwhile, the thrust south from General Steele had provided the Confederate District of Arkansas with a substantial enough degree of numerical superiority to launch a new offensive with the goal of retaking the Arkansas River Valley. Steele would return north in an attempt to re-unite with the smaller force that had been left in defense of the area, but was delayed by a contingent of cavalry from Magruder's Texas District. On March 23, 1864, Major General Sterling Price defeated the Union garrison of Little Rock, re-occupying the city before swinging west and crushing the small forces in De Vall's Bluff and Clarendon. By this point, General Frederick Steele had reached Pine Bluff, and now was in a race to reach Little Rock and retake the city before Price could arrive to reinforce the garrison. Hampered by poor weather and harassed by Confederate cavalry, they arrived south of the city a little over a day after Price, who had quickly set about fortifying it and preparing for a Union assault. Steele instead opted to march Northeast to retake Clarendon, abandoning the Red River Campaign entirely.
Further south, Banks was faring only marginally better. His repeated attempts to assault Confederate lines across the Atchafalaya river were met with high casualties. Unlike Taylor, who was continuing to receive a steady stream of reinforcements from General Magruder, as well as a number of militias drummed up from the newly retaken stretches of Louisiana, Banks was limited by the men currently at his disposal. The forces at his command had also been stripped back somewhat by Grant, who had pulled heavily from the less vital reserves and garrisons of the far west in his attempt to crush Longstreet. Banks, unaware of the extent by which Taylor had been reinforced, launched another attack on the 25th of March which initially saw minor success before a large contingent of Confederate cavalry slammed into Bank's western flank, turning them heavily. It was at this point that Taylor ordered a general advance, crossing the Atchafalaya and dealing significant casualties to the Union lines, which were by now in complete disarray. Banks' men fell into a rout, pursued by Confederate cavalry all the way to Baton Rogue. The vast majority of Banks' command had been captured or killed, with Taylor's force quickly re-occupying vast swathes of southern Louisiana which had been left with few defenders in order to support the move north. It was only with their naval control of the Mississippi river that Union forces were able to prevent a complete Confederate breakthrough. These ironclads, however, did not prevent small points along the river which were relatively undefended from being crossed by small Confederate forces. With Baton Rogue and by extent New Orleans under imminent threat of Confederate assault, reinforcements were sent from the few remaining sizable garrisons in the region- Memphis and Jackson, the latter of which would quickly be re-taken by Joseph E. Johnston's forces outside the city.
It was clear to observers on both sides that the Union position in the far west was in complete disarray. It was also the opinion of many that, while a large part of the blame could be placed on poor communication and coordination between Union commanders, the principal reason for the disastrous failure of the Red River Campaign was that Grant had severely depleted the garrisons and reserves of the region. Combined with his failure to save Sherman's army and the consistent massive losses in his region under his subordinates, his image as the savior that would sweep east and retake the momentum of the war for the Union had begun to fade. Meade, on the other hand, was simply despised. His subordinates, Union high command, Lincoln, his colleagues, and his men had all grown sick of his seemingly endless string of failures in the east, and with the extremely costly, embarrassing failure in Centreville, which had seen thousands of pointless Union casualties and the deaths of dozens of relatively high ranking officers, from major generals to colonels, it had been made abundantly clear he was in need of replacement. The only question was who was the right man for the job. Two of his corps commanders were dead, and the remaining were seen by most as somewhat incompetent. Grant's reputation, while damaged, was still enormous. However, he was drastically needed in the west, both to deal with Longstreet and to clean up the complete disaster in Louisiana, Arkansas, and Mississippi. It was with this in mind that the injured Major General George Sykes would be promoted to commander of the Army of the Potomac, under the informal understanding that Grant would take the role upon having cleared up issues in the west. However, due to an infection of one of his wounds, he would be rendered unable to hold the post, and Major General William H. French would assume what was essentially temporary command of a temporary command until either Sykes or Grant were able to take his place.
French, who was unpopular among both his peers and the army at large and possessed a poor track record throughout his military career, as well as generally poor tactical and strategic acumen, found it nearly impossible to get any of his newly subordinate officers to follow orders. They viewed him as an illegitimate and temporary commander from whom orders need not be considered. This would have disastrous effects as Lee easily stole a number of marches on the Army of the Potomac, which found itself completely paralyzed by poor communication and near-insubordinate corps commanders. Lee, eager to take advantage, had moved his left and right flanks around either side of Union forces, attempting to envelop the larger army in an imitation of Cannae. While this movement would ultimately fail, though not without inflicting severe casualties on the Army of the Potomac as it struggled and barely managed to break through Lee's right flank and prevent being separated from Washington. The Army of Northern Virginia managed to temporarily occupy Arlington and Alexandria before being pushed out by the Army of the Potomac, which formed its new position directly across the Potomac river from Washington itself. By this time, Sykes had died of his injuries, and it was clear that Grant was needed in the east. Grant, who had finally cornered Longstreet after weeks of maneuvers and skirmishes around the Tennessee river, was called to take command of the Army of the Potomac in place of William H. French, who had resigned in frustration.
With George Henry Thomas and Sherman both dead, however, he was left with few options as replacements, especially as McPherson had over the winter taken command of the Union army in Nashville. In his place, Grant left John Schofield as commander of the Army of the Tennessee, with John Alexander McClernand, who had recently been restored to command by Lincoln taking command of the first corps, James H. Wilson taking command of the second corps, Benjamin Butler taking command of the third corps, and Don Carlos Buell, recently restored to command, taking command of the fourth corps.
The departure of Grant came as an enormous relief to the Army of Tennessee, which had days before been faced with the immediate threat of attack from Grant. Longstreet gathered his chief subordinates- Daniel Harvey Hill, Patrick Cleburne, and Joseph Wheeler, to discuss a potential offensive against the Union Army of the Tennessee. While they were heavily outnumbered and in a poor position, their confidence was at an extremely high level due to the perceived incompetence of the Union commanders opposite them, who had established reputations as poor leaders and failures who only held high posts out of political considerations or friendships with Grant. This confidence was amplified by the recent performance of Confederate armies in Virginia and the far west. It seemed to many observers on both sides that the Confederacy had once again retaken the initiative, and that with only a few more major victories, the Union would finally decide the war was too costly and call for a ceasefire. It was with this in mind that Longstreet and his officers would begin drawing up their most ambitious, risky, dangerous battle plan yet.