Sickles later contended that had his salient been supported, the stampede of the XI Corps might have been avoided. He believed he had seized the initiative, improvised his own strategy on the spot, and was only cheated of victory by lack of support from an emotionally drained commander. He felt that he had saved the day and checked Jackson's advance. The evidence, however, does not support such contentions.
In fact, Sickles had accomplished nothing to stop Jackson's flank attack, and found himself instead isolated and in no position to slow or prevent the debacle on the army's right flank. When he returned to Hazel Grove, Sickles drove off a scouting party of about 200 men of the 4th Georgia Infantry. This can hardly be described as stopping Jackson's attack, which petered out long before it ever reached Sickles' position because of confusion in the underbrush and the need to reorganize. As for his brilliant night attack, witnesses reported that it was a mixed-up mess, one of the most comical episodes in the history of the Army of the Potomac. Very little of value was accomplished. Its main effect was to increase the number of casualties and deprive both armies of sleep.
Years after the battle, XI Corps historian Augustus Choate Hamlin, who had been a lieutenant colonel and medical inspector at Chancellorsville, investigated the events of that fateful day. His report was quite different from previously accepted accounts of the XI Corps' disaster. In his 1896 book, The Battle of Chancellorsville, Hamlin charged that Sickles' expedition to Catherine Furnace and beyond was the ultimate cause of the rout and the campaign's failure. Hamlin blamed Sickles because he had persuaded Hooker to allow him to make the fatal reconnaissance that isolated the XI Corps and left it without reserves. Hamlin also derided Sickles for his ignorance of Jackson's location and true intention and for the absurdity of his expedition.
Sickles clearly had failed to respond properly to the situation at hand when he advanced to create his salient. If he really suspected that Lee was attempting to flank Hooker's line, his proper response would have been to support Howard, not isolate him. He should have realized that Lee was not retreating when Birney was struck by the two enemy brigades at Catherine Furnace. That attack made it clear that there was a strong force of Confederates still massed in force on his left, apart from the marching units–and they were obviously not retreating. Yet Sickles continued to advance, completely disregarding what must have been a flanking column bent on mischief to the west.
By his hasty actions, Sickles succeeded in isolating elements of Hooker's army (his own and Howard's) at a time when a united defense was essential. Had Sickles remained next to Howard, along with Barlow's reserve brigade, he might have been able to bolster that corps and prevent or minimize the ensuing rout. In the end, however, Howard's corps was decimated, the entire army was endangered, and Sickles' own corps narrowly escaped destruction.