During these operations against Sedgwick Lee's army had been for the second time divided. A great part of it had been sent half a dozen miles or more away to force Sedgwick back to the river and across it. In the meanwhile Lee, with a mere fragment of his force, had lain in front of Hooker. Why Hooker did not fall upon him and destroy him with the eighty thousand men whom he could easily have brought to bear against less than twenty thousand, is a question that can be answered only by the reminder that Hooker was not equal to the task of successfully handling the marvelous fighting machine which the North had so successfully created. Great as he was as a fighter under some other and abler man's direction, Hooker in command of 120,000 men seems to have been paralyzed by the magnitude of his task. He left it to Lee, with his greatly smaller force to determine when and where the fighting should be done. He lay still and let Lee alone while the greater part of Lee's army was detached upon the mission of driving Sedgwick across the river and recapturing the heights at Fredericksburg. He lay still while Lee was bringing back the troops thus detached and putting himself in readiness to strike that final blow that should break the Federal lines, drive them back across the river, and make an inglorious end of Hooker's superbly planned but phenomenally ill-executed campaign.
On Monday, May 4, he had 80,000 men (Dodge) under his immediate command at Chancellorsville, with more than 20,000 under Sedgwick within easy call, as an available reinforcement. At the very most Lee could bring less than 30,000 to bear against him even if every movement in concentration should be successfully made. Yet according to his own testimony, given two years later, Hooker decided on Monday to retreat across the river. He called his major generals together "not as a council of war" he says in his testimony, but merely to find out how they felt with regard to the alternative policy of making what Hooker himself regarded as "a desperate move against the enemy in our front." That "desperate move" was the assailing of less than 30,000 men by more than 80,000 of as good soldiers as ever pulled a trigger, while 20,000 more remained within call as reinforcements.
It was decided by Hooker, against the nearly unanimous advice of his lieutenants not to make that "desperate move," and the history of war records no more lame and impotent conclusion than that. It was decided by Hooker that the great army which had made a splendid strategic movement for the purpose of fighting Lee in the open and destroying him by overwhelming numbers, should run away from him and escape beyond the river if he should graciously permit it to do so.
To that end—to render possible the escape of 80,000 resolute men from the assault of less than 30,000 of the enemy, all the engineering skill that the Army of the Potomac could command was brought to bear. It protected the roads with abattis and the bridge heads with batteries which the aggressively insistent Confederates shelled persistently. A sudden rise in the river for a time threatened the retreat with failure and placed a part of the force in danger of destruction or capture. But in the end Hooker succeeded in extricating his army from its position. Early on the morning of May 6, the last battalions of the Army of the Potomac withdrew across the river.
Thus ended in failure the most brilliantly planned attempt that had yet been made to destroy Confederate resistance, conquer the Confederate capital and make a mercifully early end of a fratricidal war of stupendous proportions.
Hooker reported his losses during the campaign at 17,285 men; Lee's loss was 12,277.
If Lee could have attacked Hooker's fleeing columns when they were huddled together at the bridge ends on the river, demoralized and without organization as they were, he might easily have multiplied the Federal loss in killed, wounded, and prisoners by two or three. General Schurz once expressed to the present historian his astonishment that Lee neglected to do this. Perhaps the best answer is given in an extract from Colonel Dodge's exhaustive history of the conflict. He writes that Lee "was doubtless profoundly grateful that the Army of the Potomac should retire across the Rappahannock and leave his troops to the hard-earned rest they needed so much more than ourselves; but little thanks are due to Hooker, who was, it seems, on the north side of the river during these critical moments that the casualties of the campaign were not doubled by a final assault on the part of Lee while we lay in this perilous situation.... Providentially the artillery of the Army of Northern Virginia had expended almost its last round of ammunition previous to this time."
Thus accident alone saved the rear of Hooker's defeated army from a disaster and demoralization comparable with that of Manassas, at a time when, in the urgently expressed opinion of General Sickles, the conspicuous rout of the Army of the Potomac would necessarily have meant the abandonment of the struggle by the North. "If," he alleged, "this army should be destroyed, it would be the last one the country would raise."
Hooker had lost, by his own incapacity, a decisive opportunity to end the war with Federal success, and Lee, because of a lack of ammunition, had lost a still more obvious opportunity to end it by a decisive triumph of the Confederate arms.