It is by now admitted that nationalism develops through transnational interaction. However, it is rarely explored how this happens – how exactly these influences happen, when, or where. After distinguishing national identity from nationalism, this paper aims at following Francis Lieber‘s early contribution to the nation-building process in the United States. From 1827 until 1835, through his literary works, he imported several institutions or theoretical bias from Prussia and Europe, with different patterns and different outcomes: the first attempt (Prussian gymnastics) did not survive long, while the reformation of educational institutions heavily relied on the European models; lastly, the Encyclopedia Americana edited by Lieber displays all the tensions within the concept of national identity, since it is imbued with different orders of local, European and cosmopolitan biases. Taken together, these processes shows, first, that the transnational interaction is not only competitive, and that cooperation and imitation are also crucial to the building of the American national identity; second, they underscore that the exceptionalist perspective – but in fact any national identity – is torn between a substantial difference’ narrative and a necessarily relational nature.