What is a summary of A People's History of the United States, chapter 9? How does it describe the evolution of slavery?

Chapter 9 of Howard Zinn's A People's History of the United States examines slavery, the Civil War, and the Reconstruction era. Zinn traces the limited successes of grassroots abolitionist movements in the late slavery era to the development of the Civil War to the brief progress experienced by former slaves to the violent, racist backlash against African Americans.

The text details the violence directed at slaves and the difficulty faced by abolitionists trying to free them, as well as the relatively limited slave revolts of the early 19th century. Most slaves did not engage in armed resistance, however, and instead attempted to flee and resisted "pre-politically," by affirming their humanity with religious expression, art, and music. Legal changes in the mid-19th century made escaping plantations and retaining freedom much more difficult for former slaves, despite abolitionists’ resistance. Additionally, the 1857 execution of John Brown and passage of the ban on mailing abolitionist literature in the south were major blows to the growing abolitionist movement.

The election of Lincoln in 1861 resulted in the secession of several states, which led to the first battles of the Civil War. Abolitionists used the war to increase their campaign for emancipation; while they differed ideologically with Lincoln, who aimed to deport ex-slaves to Africa after freeing them, the freeing of Union-state slaves with the Emancipation Proclamation was viewed as a minor success. 20% of slaves fled their plantations during the war; 200,000 total joined the Union army, and demands for equal pay were passed by Congress in 1864. The Civil War waged for four years, claiming 600,000 lives. The Union was restored in 1865.

After the war, new Constitutional amendments and racial equality laws allowed for ex-slaves to progress socially and politically. The years after the Civil War showed some progress, with the election of African Americans to state legislatures and introduction of racially mixed schools. However, backlash including the creation of the KKK, widespread murder and rape by white men in black communities, and church arsons began soon after. Coalitions between white business owners denied opportunity to black workers, popular writers used stereotypes of former slaves as violent and primitive to promote racism in society, little government reconstruction aid benefited the impoverished formerly-enslaved, and lynchings continued throughout the south. The brief progress enjoyed by African Americans shortly after the abolition of slavery quickly devolved into more violence and fear. The chapter ends with a brief examination of late-19th century black leaders, such as Booker T. Washington and W.E.B. Du Bois, and their leadership in the fight for full racial equality.