How did both David Walker and Alexander Crummell argue their cases about the future of diasporic Africans in America?

While both of these African American men were quite educated and wanted better rights for other African Americans, they had different ideas.  Walker, whose father was a slave, believed that slavery should be abolished immediately and that African Americans should be able to serve on juries and attend good schools in an attempt to promote their equality.  Walker broke with other abolitionists of the period who believed in gradual abolition.  
Crummell, an African American minister from the latter half of the nineteenth century, wanted better educational opportunities for African Americans.  He also promoted that African Americans move to Liberia.  During this time, racism was prevalent in an America that had just abolished slavery.  Many African Americans saw that there were few opportunities in mainstream society and decided to emigrate to the Western states.  Some, like Crummell, started a "back to Africa" movement in which African American people could establish their own society.  The "back to Africa" movement would gain some traction, though few African Americans had the means or the desire to do it.  
https://www.biography.com/writer/david-walker