Another excerpt from Volume 3: Barren Victory; detailing the reaction of various members of the administration in Washington upon learning the details of Rosecrans’s defeat:
Through the night and into the early morning hours of September 21, telegraph wires across the North hummed with constant activity. In Washington DC, President Lincoln, Secretary of War Edwin Stanton and Union General-in-Chief Henry W. Halleck waited for news, pouncing on every morsel, and firing off wire after wire in response. To Rosecrans, Lincoln wrote at 12:35 a.m.: “Be of good cheer. We have unabated confidence in you and in your soldiers and officers. . . . I would say save your army by taking strong positions until [Maj. Gen. Ambrose] Burnside joins you, when I hope you can turn the tide. . . . We shall do our utmost to assist you.” Burnside, whose forces in East Tennessee were the closest possible source of reinforcements for the Army of the Cumberland, now figured prominently in Lincoln’s thoughts. At 2:00 a.m., the President wired a terse, unequivocal order to Burnside: “Go to Rosecrans with your force without a moment’s delay.”
To those around him, the President clearly appeared downbeat. He had been so for several days, fearing the worst. Those fears were now confirmed. In the small hours of Monday morning he visited his private secretary, John Hay, barging into Hay’s bedroom while the latter was still abed. “Well, R[osecrans] has been whipped as I feared. I have feared it for several days. I believe I feel trouble in the air before it comes,” blurted the frustrated commander-in-chief. On the subject of Burnside, Lincoln vented his spleen. “Instead of obeying the orders . . . and going to R[osecrans],” he exploded in clear disgust, “[he] has gone up on a foolish affair to Jonesboro to capture a party of guerrillas.”
Especially vexing was the discovery that Robert E. Lee sent Longstreet’s entire corps to reinforce Bragg, all done directly under the nose of a curiously passive Union Maj. Gen. George G. Meade. Meade and the Army of the Potomac sat quietly at Culpepper, Virginia, while Lee coolly reduced his own forces by a third. “I asked what Meade was doing with his immense army,” noted Secretary of the Navy Gideon Welles in his diary, given “Lee’s skeleton and depleted show . . .” Again Lincoln gave voice to his dismay. “It is . . . the same old story of this Army of the Potomac. Imbecility, inefficiency – don’t want to do – is defending the capital. . . . Oh, it is terrible, terrible, this weakness, this indifference, of our Potomac generals.” Welles felt Halleck should share equally in the blame. “General Halleck has earnestly and constantly smoked cigars and rubbed his elbows,” snorted a derisive Welles, “while the rebels have been vigorously concentrating their forces to overwhelm Rosecrans.”
 Martin Burlingame and John R. Turner Ettlinger, Inside Lincoln’s White House: The Complete Civil War Diary of John Hay (Southern Illinois University Press, 1997), 85. Prior to the fight at Chickamauga, Burnside and Rosecrans had been in regular communication. With the capture of Chattanooga on September 9, it looked to both men as if Bragg were retreating, leaving Burnside nothing to fear from that quarter. Accordingly, Burnside took that part of his force not tied down occupying Knoxville towards Jonesboro Tennessee, near the Virginia-Tennessee border, to try and secure his northern flank. A small force of Confederates under Major General Samuel Jones still controlled southwest Virginia and, if reinforced, could pose a threat to Burnside’s control of East Tennessee. At Jonesboro, Burnside was about 100 miles northwest of Knoxville, and more than 200 miles from Chattanooga.