Does the Bible support slavery and (white) superiority in the context of American slavery?

Slavery existed as a fact of life in the ancient world, and the Bible mentions slavery in many places. - When the Bible speaks of slavery, is it supporting it, or merely describing it? Does the Bible encourage slavery, merely condone it, or is it actively against it? - What Scripture addresses the treatment of slaves, and how does this compare with how other nations in the same time period addressed their slaves? - Along these same lines, what was the role of Christians in the slavery debate? Since the status of Africans was in many ways the philosophical underpinning of their servitude, were there any particular denominations that were distinguished in their rejection of this prevailing attitude. Put another way, are passages about slavery in the Bible prescriptive or descriptive in their treatment, and did the Bible have any discernible impact on the actual practices of Christians?