Haynes continued to write and speak about slavery. His contemporary white republican and abolitionist thinkers did see slavery as a liability to the new country, but most argued for eventual slave expatriation to Africa. The American Colonization Society (founded in 1817) was the largest colonization group. Included among its supporters were people such as James Madison, James Monroe, Henry Clay and Daniel Webster. The ACS was strongly supported in Vermont. In contrast, Haynes continued to passionately argue along Calvinist lines that God's providential plan would defeat slavery and lead to the harmonious integration of the races as equals.