The following entry will outline the central arguments in favour of and against the right of the state to revoke citizenship. According to those who defend the right of states to revoke citizenship, we must understand the relation between citizens and their state in terms of a contract, according to which each party has particular duties to carry out. Where someone has committed a particular set of crimes, they can be understood to have violated the terms of the citizenship contract, and are thereby no longer entitled—by their own actions—to the protection offered by the state. A second defence recommends revocation as an appropriate and fitting punishment for a particular subset of especially egregious crimes, including terrorism, since anyone who commits these crimes attacks the foundations of the state and correspondingly deserves to be excluded from its protection. There is a much wider range of arguments against the right to revoke, perhaps reflecting that none seems to effectively rule it out absolutely. According to those who oppose the right of states to revoke, the laws are problematic because they are likely to generate statelessness; because they are a violation of the equality to which democracies are committed; because they are likely to be arbitrarily applied; because they are a violation of democratic principles more broadly; and because they represent an abandonment of a collective, global, responsibility to fight terrorism.