By exploring Russia’s activities from the fall of the Soviet Union to nowadays, this paper examines how Russia uses nationality (understood in a wide sense of the term) as a political, economic, and cultural tool to justify expansionism. Russia, so it seems, is using grey areas in international law to implement a policy whose legal implications are in breach of the key principles of the UN Charter relating to international peace and security. It is argued that the policies and tools (eg conferral of nationality, support for the right of self-determination, protection of nationals abroad, etc) developed and used by Russia are not necessarily unlawful per se; they can indeed in some instances be justified under international law as they fall within the grey areas of international law. That being said, the situations created as a result of this policy are often unlawful (eg recognition of a State that is part of the territory of another State, occupation and annexation, etc.). The paper concludes that Russia, by using its ‘nationals’ abroad and legal grey areas, is attempting to rewrite the rules carefully crafted post-1945, thereby allowing for interference in neighbouring States to become an established international custom.