Geoff, that was Meade's victory and he made Lee attacked him instead of the Federal forces attacking Lee's army.  It was defense that won that battle and gave Lincoln a big victory.  Then Lincoln starting calling for unconditional surrender from the south. Custer must be given his dues at Gettysburg because he stooped lee's army from attacking from the rear.   Poor scouting can cause military defeat.   A good example was at Midway, the Japanese didn't scout the area and the US commander had the area scouted.    Custer made the same mistake against Chief Sitting Bull at the Battle of little big horn.