Final answer:
Vognar's comment on American Gangster suggests that the film provides a perspective on the systematic failures within American institutions, as reflected in the African American experience with inequality and injustice. Black gangster films are characterized by moral ambiguity that challenges traditional notions of right and wrong, highlighting the impact of oppressive societal structures on personal choices and morality.
Step-by-step explanation:
When Vognar states that American Gangster paints the 'shadow history of institutional decay,' he suggests that the film explores the underbelly of American history and institutions that have failed to serve justice and equality, particularly in the context of African American experiences with systemic issues such as racism, corruption, and socioeconomic disparities. The portrayal of a black gangster protagonist challenging the established system reflects the broader societal issues that have historically marginalized black communities.
Black gangster films often delve into the 'moral ambiguity' by showcasing characters that may engage in illegal or violent activities, but who are also shaped by the oppressive societal structures they are born into. These films prompt viewers to question the notion of morality in a world where the rules are skewed against certain groups. As a result, these films provide a complex look at the characters' motivations and the choices they make, often blurring the lines between right and wrong.