I think about this often. After Gettysburg, Lee's army retreated and Meade did not pursue him(Which was one of the worst mistakes of the war). Therefore, The ANV was not beaten Vicksburg had fallen and that was a terrible loss for the Confederates. Those two combined were very significant to the outcome of the war. But I think that if The Confederates were successful in laying siege to the Union army at Chattanooga and were able to capture the entire army- as Grant had done at Vicksburg- they may have had a chance at overall victory in the months to come- or a negotiated peace(Which is a Southern Victory). What do you think?