This chapter analyzes the role of the (human) right to family life and family unity in overcoming migration restrictions during the Cold War era. Family reunification was not just a way of overcoming emigration restrictions in the socialist East. It was also a possibility to circumvent restrictive immigration rules in Western countries like the Federal Republic of Germany. The right to the family thus contributed to greater freedom of movement. The chapter will show how after an initial period of limited (ethno-)humanitarian East-West migration after the Second World War, human rights norms protecting the family turned from a generic principle for the reconstitution of postwar societies into a key motor for enabling both inward and outward migration, thereby undermining state sovereignty in migration matters—crucially, though, in conjunction with constitutional norms on the national level.