Based on President Volodymyr Selensky's invitation that "anyone who wants to join the defence of Ukraine, Europe and the world can come and fight side by side with Ukrainians against Russian war criminals", it is appropriate to take a closer look at the possible consequences for Austrian citizens who comply with this invitation. Section 32 of the Citizenship Act 1985 (StbG) contains a separate deprivation of citizenship:
§ 32. A citizen who voluntarily enters the military service of a foreign state is to be deprived of citizenship.
In contrast to the (automatic) loss of citizenship, e.g. in the case of voluntary acceptance of a foreign citizenship, the withdrawal takes place within the framework of an official procedure and is decreed by a decision of the citizenship authority. However, the legal formulation "is to be deprived" makes it clear that if the elements of the offence are present, the authority has no discretionary power and has to decide for the withdrawal. However, the withdrawal presupposes voluntary entry into foreign military service; someone who is called up as a dual citizen (in this case, for example, Austria and Ukraine) on the basis of general compulsory military service does not voluntarily enter foreign military service.
However, even if one does not become part of the state armed forces of a foreign state, there is a certain risk for the deprivation of citizenship according to Section 33 para 2 StbG because of active participation in armed combat abroad:
A citizen who voluntarily participates actively for an organised armed group in combat operations abroad in the context of an armed conflict is to be deprived of citizenship if this does not render him stateless.
In response to Selensky's call, the British Foreign Secretary and the Latvian Parliament have already declared that they would not only leave this option open to their own nationals, but would also partly support it. In Austria, such support measures from the state side would probably be problematic with regard to neutrality and are probably not to be expected. An "exemption" is also not provided for in the citizenship law and due to the lack of discretionary powers in the withdrawal, not even the citizenship authority could "turn a blind eye".
Consequently, Austrian citizens who voluntarily join the Ukrainian army or participate in combat operations in Ukraine are at considerable risk of having their citizenship revoked.