"...estimates that it would take three months to fully reconstitute Army Command Ohio after the grueling attritional hell of the past year, but Pershing was curtly nudged multiple times by Bliss in a way that subtly but very decidedly was designed to let him know he did not, in fact, have until September to put the Confederacy on her back heels again. Thus, on August 10th, 1915, the newly-constituted First Field Army - at a full-strength twenty-four divisions organized into six corps - marched out of its camps in western and central Tennessee, the largest armed force assembled under an American flag yet in the war, as the Tullahoma and Chattanooga offensive began. They were supplemented by smaller commands under General Ed Wittenmyer, with three divisions, and General Joe Dickman, with four divisions, attacking from southwest and northeast.
Pershing's approach was based on strategies drawn up by Farnsworth and Lenihan before the great command reorganization of May 1915 and refined since the Long Branch Conference. The First Field Army, one of the largest forces ever assembled in the history of the Republic, would press out from the Nashville Basin towards the Confederate pickets east of Murfreesboro, with their main objective securing the Eastern Highlands and the Duck River, particularly the strategic crossing at Shelbyville. From Shelbyville, the First Army would attack Tullahoma, split in two and secure the two main cities on the Tennessee River - Chattanooga in the east, Huntsville in the south. The first objective was in order to set up for an invasion of Georgia, likely in in early 1916; the second was to screen against any attacks towards Tennessee from Alabama's industrial heartland. Dickman's divisions would attack at Corinth, Mississippi - a critical rail juncture in that state's far northeast - and then march alongside the Tennessee towards Huntsville, pincering the city from both west and north against the Appalachians and the river.
Wittenmyer - a staff general who had acquitted himself well in the East under Liggett and who had been reassigned to Tennessee at Pershing's request - would meanwhile take his smaller force and press towards Knoxville, a mountainous mining city east of the Cumberland Gap that had been mostly secured by American forces since earlier in the spring in the vicinity of Williamsburg, Kentucky. Knoxville was a hugely important source of coal and other minerals for the Confederate war machine, lay on a key trans-Appalachian railroad route between Virginia and the Midlands, and by that same token sat north of Chattanooga in the Appalachian Valley; a Confederate force could easily collapse down onto Pershing's forces from there with little issue. In all, the strategy would be two smaller offensives directed by Wittenmyer and Dickman on the periphery of Pershing's First Army punching its way across the Duck and through Tullahoma towards the Tennessee River and the critical mountain passes to Georgia, what War Department correspondence called "the three-headed monster."
Of course, such offensives were easier said than done, and all three thrusts met stiff resistance. Due to the First Army's position deep inside Confederate territory, it was harder to place aircraft at landing fields in proximity due to fears of Confederate sabotage and thus Pershing lacked the air cover from Maryland or West Virginia that was becoming a staple of battles in Virginia; furthermore, the collapse of Nashville's defenses had seen Beaumont Bonaparte Buck relieved of command in the Midlands and replaced with Robert E. Lee III, whom it was hoped would channel his ancestor's tenacity and tactical acumen into victories in the field. His cousin, George Bolling Lee, was in defense of Corinth and had spent the time since the initial press of Dickman's forces back to Memphis in the early spring building the city into a fortress that would have impressed its Peloponnesian namesake, a maze of trenches, Maxim gun nests and hardened artillery. Dickman's attempt to seize it in mid-August ended in fiasco, and he would settled in for a long siege in the area that would last deep into early autumn, slowing down Pershing's offensive plans considerably. Wittenmyer had little more luck - his offensive was harried as early as Carthage on the Caney Fork, repulsed briefly at Gordonsville, and stopped in its tracks entirely at Cookeville on August 20th with a decisive defeat thanks to a cavalry attack by Confederate General Richard "Dixie" Taylor, who had been a standout in West Tennessee earlier in 1915 and now enjoyed a command of his own on the approaches to Knoxville. Both armies fought again Macedonia and Sparta August 24th-25th, in a bloody orgy of violence, with Wittenmyer emerging victorious this time but having to retrench his forces to regroup after the ugly battles to advance barely 100 kilometers over two weeks from his base camp in Lebanon.
Pershing had at least marginally more success, but did not want his operations to get too far ahead of his flanking offensives. On the 13th, he fully secured Murfreesboro and on the 16th had managed to press across the Eastern Highlands in the Battle of Bell Buckle; the next two weeks saw the hideously violent Battle of Shelbyville, in which his forces took disproportionate casualties but with the support of landships were able to finally break across the Duck to the west of the city on the 1st of September and by the 4th cut around to the south of Tullahoma, threatening Lee's headquarters, only to be defeated at Lynchburg thanks to the first significant Confederate air cover of the war. Pershing was stunned - the ferocity of fighting in Tennessee was over and above even what Mexicans had doled out at Los Pasos. Grievously wounded as Dixie was after the Black May, four months later the attacks were just as stiff, and as the war reached its two-year mark days after the fiasco at Lynchburg, Pershing came to realize just how long and ugly the year of fighting ahead of him was likely to be..."
- Pershing