To the citizen, Irish emigrants in America are part of the Irish nation, and so Bloom's answer has unacceptable implications. Throughout Ulysses, written as the Irish fought Britain and each other to make the Irish Free State between 1916 and 1921, Joyce uses the story of Odysseus's homeward journey to question the meanings of 'home' and 'nation,' and of keeping faith with a national culture while living elsewhere, in individual or communal exile. Ulysses examines the idea of longed-for but exigent home that the nation-state would become. (3)
And here is where he makes the connection between transnationalism and the idea of diaspora:
We use 'diaspora' provisionally to indicate our belief that the term once described as Jewish, Greek, and Armenian dispersion now shares meanings with a larger semantic domain that includes words like immigrant, expatriate, refugee, guest-worker, exile, community, overseas community, ethnic community. This is the vocabulary of transnationalism, and any of its terms can usefully be considered under more than one of its rubrics." (4-5)
Final interesting quote:
Diasporas are emblems of transnationalism because they embody the question of border, which is at the heart of any adequate definition of the Others of the nation-state. The latter always imagines and represents itself as a land, a territory, a place that functions as the site of homogeneity, equilibrium, integration; this is the domestic tranquility that hegemony-seeking national elites always desire and sometimes achieve. In such a territory, differences are assimilated, destroyed, or assigned to ghettoes, to enclaves demarcated by boundaries so sharp that they enable the nation to acknowledge the apparently singular and clearly fenced-off differences within itself, while simultaneously reaffirming the privileged homogeneity of the rest, as well as the difference between itself and what lies over its frontiers. (6)
In effect, diaspora studies must be allied to ideas of heterogeneity, the celebration of diversity rather than unity in the national imaginary. MN's films fit this paradigm quite closely. Even her "nationalist" films have a diasporic element to them.