Answer: Robert E. Lee was the most successful Confederate military leader during the American Civil War (1861–1865). This also made him, by virtue of the Confederacy's defense of chattel slavery, the most successful defender of the enslavement of African Americans . late in the war,slaves and freeing all who served honorably in the cause of Confederate independence. He did so not Lee supported arming some because he harbored secret abolitionist sentiment, as some have argued, but because he believed it necessary to win independence.