"[I]f some doubt may be cast upon the language of Mr. Madison at times, at others he stands out for at least as much admiration as may be bestowed upon a set of man who have rarely been subjected to unfavorable criticism. He squarely announced himself opposed to the slave-trade, and stated that he did not think it right to admit the idea into the Constitution that its framers considered the slaves as property, or that there could be property in man. And no doubt he said honestly that much had been gained by closing the slave-trade in 1808, forever."