What changed in the period from the 1950s to the 1960sthat brought these changes about?

At the high point of Reconstruction,” according to professor Chandler Davidson, “About two thirds of black males cast ballots in presidential and gubernatorial contests.” In the 1890s and first years of the twentieth century, “the doors to black political participation were forcefully slammed shut,” and African American male voter registration plummeted into the single digits in many southern states. By the late 1960s, more than sixty percent of voting age African Americans had registered to vote. What changed in the period from the 1950s to the 1960sthat brought these changes about? AND, who do you think, was most responsible for these changes? 
( Per the prompt, your objective in this essay is to craft an argument that assesses the transformations in voting rights for African Americans during the middle of the twentieth century, with particular focus given to answering the following two questions: 1) What changed in the period from the 1950s to the 1960s that brought these changes about? AND 2) Who, do you think, was most responsible for these changes?)

Rules:
1. 3-4 pages
2. Double spaced, 12-point font
3. Standard margins—Approximately 1.25 on left and right margins and 1 on top and bottom
4. In crafting your essay, you will want to construct a clear thesis and draw on evidence from the sources described below.
5. Only use these sources below.

Sources:
1. Reading: Foner, “The Freedom Movement” (pages 968-979) (attachment)
2. Reading: Foner, “The Civil Rights Revolution,” “The Kennedy Years,” “Lyndon Johnson’s Presidency,” and “The Changing Black Movement” (pages 985-1002) (attachment)
3. Woman Linked to 1955 Emmett Till Murder Tells Historian Her Claims Were False – The New York Times (attachment)
4. President Lyndon B. Johnson’s Voting Rights Act Speech
Link: https://www.youtube.com/watch?v=VbFmicUTb_k#action=share
5. Brothers in Arms
Link: https://www.npr.org/templates/story/story.php?storyId=1908299