In what ways was the theatre used as a vehicle for promoting civil rights in the postwar era?
I would suggest taking Lorraine Hansberry and Leroi Jones/Amiri Baraka and compare the agendas of their plays to show how theatre reflected the variety of approaches espoused by the Civil Rights Movement. These varied from the non-violence of Martin Luther King to the more aggressive militancy encouraged by Malcom X and the Black Panthers.
Hansberry's play A Raisin in the Sun (1959) was the first by a black playwright to be staged on Broadway. It stresses the frustrations and conflicts brought about by poverty and inadequate living conditions in an African American family. While the play highlights the anger of the members of the Younger family towards the larger American society for their condition, it also seems to favor an integrationist agenda in portraying their final move out of the South Side black ghetto of Chicago into the Clybourne Park area.
In contrast Amiri Baraka's plays such as Dutchman (1964) and The Slave Ship (1967) reflect his own transition to an increasing radicalism and black nationalism. Such transition is also reflected in the playwright's change of his name from LeRoi Jones to Amiri Baraka. His plays reject the traditional notion of redemption through sacrifice and argue for the active struggle of African Americans against white oppression.