In recent years, due to the threat of terrorism, there has been a return of banishment, in contemporary terms better known as citizenship revocation or denationalization. The aim of this thesis is to critically assess the most common arguments used for and against liberal nations’ power to revoke citizenships as punishment and as a means to protect national security. This thesis presents an argumentation analysis of some of the most common philosophical arguments used for and against citizenship revocation in liberal democratic states. The arguments are first described and then evaluated based on their evidentiary strength in order to determine whether citizenship should be unconditional. The thesis concludes that the argumentation analysis indicates that citizenship should be unconditional in a liberal democratic state.