I agree with Anaxagoras. Hooker missed a great chance in May 1863 to win the War,or at least to push to Lee back towards Richmond. Chancellosville is always seen as a great Lee victory, but it should have been a Hooker victory. By April 29th 1863, Lee for the first time had been surpised by a Union General . Hooker had placed three corps in his rear, whilst Sedgewick still faced him at Fredericksberg, he was about to be crushed in between two forces. There are two what is at this Point. First on the 29th, General "Stonewall" Jackson was about to go over onto the offesive at Fredericksberg as Sedgwick paraded his divisions, Jackson wanted to attack and occuply the plain south of the Town. Lee disagreed with the plan and after looking at the ground and plan he called off the assault. Imagine Jackson attacks hastly, with heavy union cannon on the far bank of the River they could have poured fire on Jackson's force. On hearing of Jackson's bloody attack, Lee would now been fighting a battle as the large union force advanced on his rear. On hearing that Lee was now attacking Sedgwick, Hooker doesnt apply the brakes on April 30th and go onto the defensive, indeed the Army of the Potomac does as Corps commanders Meade and Slocum planned as they Corps joined hands on April 29th at Chancellorsville. " This is splendid, Slocum; hurrah for old Joe! We are on Lee's flank and he doesn't know it yet. You take the Plank towards Fredericksberg and I will take the Plank Road, and we will get out of the Wilderness".
For some reason, Hooker lost his bottle, with Lee held in place, he ordered Meade and Slocum to halt.It would be another two years for Lee to be in such a position and the chance to Win the war in 1863 was lost.