The historical evolution of political systems has led to the development of two models of citizenship acquisition: jus sanguinis (right of blood) and jus soli (right of soil). In certain situations, the convergence of these principles may necessitate the application of conflict-of-law rules.
An interesting example is provided by a judgment of the Supreme Administrative Court (ref. no. II OSK 1048/23), issued in 2025 but based on a Polish Act of 1920; it concerned the determination of the citizenship of a person of Polish descent whose ancestors were born in Brazil.
Contrary to the position of the Minister of the Interior and the provincial administrative court, the Supreme Administrative Court held that the acquisition of Brazilian citizenship by virtue of jus soli did not result in the loss of Polish citizenship acquired in accordance with jus sanguinis. This is not precluded by the provision of the Polish Act of 1920, which excludes the possibility of a Polish citizen holding the citizenship of another state.
The Supreme Administrative Court’s ruling highlights how important it can be for those applying for Polish citizenship to gather information about their ancestors, even those living in the distant past.
Brazilian citizenship laws and the NSA ruling are discussed on our blog L explorers by GWW’s partner, Aldona Leszczyńska-Mikulska, LL.B.
The article is available here: https://lexplorers.pl/nabycie-obywatelstwa-polskiego-przez-obywatela-brazylii-i-kwestia-podwojnego-obywatelstwa/.