With the advantage of hindsight, it’s easy to say that Longstreet should have disobeyed Lee and asked for forgiveness later. By the same token, it’s easy to say that we would have followed Longstreet over lee today. However, what would have happened if Longstreet did that. We can assume he would have been relieved of his command at best; and chastised, prosecuted or hanged at worst. The same could be said for soldiers in the unit. It all comes from a culture created at the top where an oft-tyrannical leader can be unpredictable except in his unwillingness to listen to new ideas. Ultimately, I don’t know if Longstreet could have convinced Lee to withdraw. At this point of the war, Lee was convinced he could and needed to end the war in Gettysburg.