The moral arc of history ideally bends towards justice but just as soon as not curves back around toward barbarism, sadism, and unrestrained chaos

Kara Walker deliberately uses “weak” or “subaltern” forms such as drawing instead of painting to survey the traumas of American history, specifically those left by the history of slavery and segregation. 
This large drawing acts like a macabre, abbreviated epic of African Americans, from their deportation by slavers and the ensuing crimes they endured, including rape and murder, all the way to the misdeeds of a segregationist society and the lynchings perpetrated by the Ku Klux Klan, a terrorist, white supremacist secret society. In the background is former President Barack Obama giving his famous speech A More Perfect Union in 2008, shortly before his election, his figure addressing the complexity of this history of which he himself is a reflection. 
The unfinished nature of the drawing is coupled with the brutality of the historical facts it depicts. The exhibition of this drawing was a source of huge controversy in the United States, even within the African American artistic community. For Kara Walker, confronting the public with the violence of historical realities remains the only way to free ourselves of the weight of the past..