Final answer:
The treatment of Irish immigrants and the redefinition of Jewish identity post-WWII are examples of racialization, where racial categories were constructed leading to discrimination. This process was supported by societal attitudes and government reports like the Dillingham Commission.
Step-by-step explanation:
The phenomenon described by the treatment of Irish immigrants around 1880 and the shift in perception of Jewish identity after World War II is racialization. Racialization is the process by which societies construct races as real, different, and unequal in ways that matter to economic, political, and social life. This occurrence is distinct from discrimination, ethnicity, or assimilation, although these concepts often intersect with racialization.
In the context of the question, racialization transformed the Irish and Jewish identities into distinct races in the perceptions of the established American society at the time, leading to discrimination based on these constructed racial categories.
During the late 19th and early 20th centuries, immigrants to the United States, such as those from Ireland and Eastern Europe, faced intense discrimination and prejudice as they were seen as distinct races. This was reinforced by the findings of the Dillingham Commission and the treatment of immigrants in the society of the day. Even though the process of assimilation eventually led to a blurring of these constructed racial lines, the initial impact of this racialization resulted in significant hardships for these groups.