In the 2013 Hollywood film "Lee Daniels' The Butler", Forest Whitaker plays the eponymous butler who is a witness to much of American history in the 20th century.
What is common to the roles played in this film by Robin Williams, John Cusack, James Marsden, Liev Schreiber, Alan Rickman, and Eric Street? (If fictional versions in 2013 can be included, add Jamie Foxx and Aaron Eckhart to this list.)