Slavery and Economics

While writing a paper for Theology of African American Music, I had the following thought(s).

To what degree did slavery allow the United States to become a world economic power? It seems to me that the U.S. was the largest slave-holding nation, and it is definitely true that the American economy hinged on slave labor for some time. So the question is if the exceptionally cheap labor provided by slaves gave an extraordinary leg up to America, helping catapult it to the position in the world it has enjoyed for so long. That is not to say that I think that slavery is any way justified by the possible impact it had on the American economy - no person has the right to exercise indomitable will over another in any circumstance.