In Germany it is possible to own dual citizenship. On page 169 Hortons says "political obligation is conceptually connected to membership of a particular polity". How do we cope with the question of political obligation if there is not only one polity?
In addition Horton says that the connection between membership and obligation is mediated through a sense of partial identification with the political community. What if people live in a country and identify with a different political community? For example turkish people who live in Germany but identify with Erdogan: a few days ago two football players took a picture with him signing a jersey and one of them added "to my president".