The story of British abolitionism, its many failures and long overdue success, is a lesson in the limits of reform. Lacking a wider context of change, reform in one sector is likely to fail or be indefinitely delayed. British radicalism in the 1790s was confined to a small number of groups with just a few hundred (or at most a few thousand) supporters in a population of nearly 10 million. It could not marshal anything close to the strength necessary to effect radical goals of general slave em...