Thank you for all the links. Another question that immediately comes to mind after beginning to read some of the info in the links:
Having failed as a businessman throughout his entire life, could his mid-life decision to fight slavery by any and all means, been partly fueled by anger and frustration at a sense that he was a failure, and abolition was something he was determined not to fail at? I'm not implying that he didn't genuinely believe that slavery was evil.