Historians say it was the high watermark of the Confederacy. As Douglas Southall Freeman wrote, it was late in the afternoon, but it was high noon for the Confederacy. Lee knew the implications of this defeat, he knew his army could be destroyed on the ground on which it stood, he knew that they might never make it back across the Potomac, he knew that at best the south faced a war of attrition against overwhelming odds which it was most unlikely to win. We know Lee knew this because he offered to resign.
As he advanced towards his bleeding troops, he kept repeating, "it is my fault, it is my fault, it is all my fault."
It is in shattering defeat that true character is revealed and it is one more illustration why one is justified in saying, Lee: The noblest and sublimest American of all.