In Chapter 5 of Immigrant America, "From Immigrants to Ethics", Portes and Rumbaut deal with the complex themes of identity, citizenship, and political participation. Much of their discussion in this chapter revolves around a repudiation of the controversial thesis put forward by the famous American political scientist Samuel P. Huntington. He has argued that Hispanic immigrants are undermining American national identity. This is because, so the argument runs, these immigrants' identities are transnational; that is, they operate across international boundaries.

Portes and Rumbaut seek to counter this argument by emphasizing that transnational identities are not necessarily incompatible with loyalty to the United States. As they point out, even those immigrants with transitional loyalties assimilate into American life and culture and develop a profound loyalty to the United States. Portes and Rumbaut, therefore, conclude that restrictionist fears of a separatist movement among Hispanic Americans are greatly exaggerated.

In a historical comparison of Cuban and Mexican-American politics, Portes and Rumbaut reveal that, despite differences, their respective group experiences share telling similarities. For instance, both groups mobilized in response to discriminatory events, and mobilizations along ethnic lines have generally trumped class concerns. One could argue that it is the general absence of class concerns among Cuban and Mexican-Americans that has facilitated their assimilation into American society.