At the bottom of page 20, Sakai suggests
The Northern States had slowly begun abolishing slavery as early as Vermont in 1777, in the hopes that the numbers of Afrikans could be kept down. It was also wide- ly believed by settlers that in small numbers the "child- like" ex-slaves could be kept docile and easily ruled. The explosive growth of the number of Afrikans held prisoner within the slave system, and the resultant eruptions of Afrikan struggles in all spheres of life, blew this settler illu- sion away.
This is a bold assertion. What supports it?
Interesting question. In addition to this, was the American abolition movement largely supported by religious institutions, or rather pragmatic/ secular moralists?