Who is Mr Jamison and why does Harlan Granger hold a grudge against him?

Mr. Jamison is a white lawyer in the novel "Roll of Thunder, Hear My Cry" by Mildred D. Taylor. Harlan Granger holds a grudge against him because Jamison represents the interests of the Black community, particularly in their fight for fair treatment and land ownership. Granger, who is a racist and seeks to maintain white supremacy, resents Jamison's support for the Black families, as it threatens his power and influence in the region. This animosity reflects the broader racial tensions in the story.