The nature of the term "white trash", the people to whom it has been applied, and the motivation of people applying the term is studied in connection to racism and politics. In full historical context the term is difficult to define and any definition must be considered with respect to the context in which the epithet was applied. For example, the racial meaning of "white" has changed. 150 years ago immigrants from mediterranean Europe would not have been considered "white". At present, the U.S. census would consider these same people, such as Italians and Italian Americans to be "white".
Some people argue that, "white trash," is racist not because it includes the word, "white," but because it implies that trashiness is the normal state for black people and thus when a white person is trashy it must be specified that the person is white.
Of these terms, White Trash is probably the most extreme. For example the term Redneck has been "reclaimed" as a self referential name by whites who are proud of their rural roots. However, no one would proudly call themselves white trash.