PETER J. SPIRO
Citizenship practices have been thought the last bastion of national sovereignty. As international norms have aggressively invaded virtually every sinew of domestic governance, nationality law has remained largely immune to any acknowledged constraint from beyond. As a doctrinal matter, it has been allocated (in the characterization of a prominent international pronouncement on the question) to a "domain resérvé" in which states are free to rule according to their own preferences. But this regime is showing early signs of slippage, and is unlikely to persist into the future.
Nationality law was in fact once within the unfettered discretion of states. To the end of reducing related frictions among states, some nationality practices lost full recognition at the international level as a matter of choice of law, and many states entered into consensual, bilateral arrangements to prioritize competing state claims to individual nationals. These developments were oriented only by state interests, not those of individuals, and by the maintenance of international order. For domestic purposes, determinations of nationality were left wholly within state discretion. The international community took no cognizance of nationality as an individual right.
At least as a discursive matter, that changed in the wake of the Second World War. Statelessness, which had previously been framed by the order paradigm, was acknowledged to implicate individual rights. Even as the right to a nationality was articulated, however, it was not made actionable against any particular state. Some nationality practices were more concretely implicated by the human rights revolution. Widely subscribed international women's rights conventions have mandated gender equality in domestic measures relating to the acquisition and loss of citizenship, and human rights norms now limit state power with respect to the termination of nationality. Some of these constraints have emerged as clear norms of international law, enforceable directly against states.
Even as such, however, as far as they went these standards only peripherally affected state capacity to delimit membership. A state could not extend those human boundaries so far as to trespass on the sovereign rights of other states,