Iseult Honohan On the other hand, we also see here the way in which citizenship can be subject to a process of attrition. We can identify one pattern where citizenship attribution on the basis of birth in the state is superseded by descent from a citizen, and this is further narrowed to restricted national groups; finally, citizenship is retrospectively revoked from those who are represented as failing to meet these redefined criteria for citizenship. These cases also remind us forcefully that citizenship status is the tip of an iceberg, depending on secure documentation, of place of birth, of ancestry, of status, from birth registration onwards. While these are taken for granted in many states, their absence, whether due to administrative limitations or to restrictive access to basic identity documentation, puts citizenship at risk when the status of citizens is put in question by the state. Even if states have the right to set the conditions for acquisition of citizenship, these cases further highlight the way in which broad state powers to revoke citizenship erode the security of citizenship itself, and confirm the need for constraints on such powers. 4 Robert Schuman Centre for Advanced Studies Working Papers