In the final years of his political career, President John Quincy Adams was well known for his objections to slavery, with rival Henry Wise going so far as to label him "the acutest, the astutest, the archest enemy of southern slavery that ever existed." As a young statesman, however, he supported slavery. How did the man who in 1795 told a British cabinet officer not to speak to him of "the Virginians, the Southern people, the democrats," whom he...