Ukrainians released from detention – is less on the margins than before. Yet it took a case before the Russian Constitutional Court and the ECtHR to help reach this outcome and secure the rights of many de facto stateless former USSR citizens in Russia. Conclusion This paper demonstrated how statelessness, if strategically challenged, may become a catalyst leading to legally productive changes for other noncitizens – or de facto stateless persons – in precarious legal situations. This discussion was contextualised to the specific conditions of post-Soviet Russia, where, thirty years since the dissolution of the Soviet bloc, there are still people whose inclusion, dignity and recognition of full personhood are inhibited by the lack of any other citizenship than that of the (non-existent) Soviet Union. The decision of the Russian Constitutional Court in Mskhiladze had real-life repercussions for securing a number of releases from detention of many former USSR citizens, but also other undocumented migrants who had no country willing to ‘take them back’. The greatest impact of the Mskhiladze ruling could be observed among a relatively new group of de facto stateless persons in the post-Soviet space: Eastern Ukrainians from the Luhansk and Donetsk oblasts, who left their homes due to the military conflict. Although many of them were given temporary asylum and ultimately citizenship in Russia, some did not manage to secure a legal status. Their detention soon proved indefinite, as Ukrainian authorities were unable to corroborate the fact of their citizenship. The immigration lawyers of the ‘Migration and Law’ network activated the Mskhiladze judgment to obtain their release from detention, attesting to the legal productivity of statelessness. Following the case of Mr Mskhiladze and its wider consequences among undocumented Ukrainians in Russia, revealed an intricate relationship between de jure and de facto statelessness. De jure statelessness, if strategically challenged, can be useful for effectuating rights and can pave the way towards achieving better legal 20