The article analyses constitutional politics in the German Länder in the field of minors’ rights. Since this issue seems a purely legal matter dealt with at the federal, European and international level, we should expect similar, almost identically shaped policies at the Länder level. However, the analysis brings considerable variations of constitutional activities in this field to the fore: time, frequency, and contents of respective initiatives vary significantly in the period from 1999 to 2014. These variations were due to different party strategies, diverging party platforms and majority constellations in the Länder. The analysis also shows that the public arguments brought forward in favour of constitutional amendments refer only weakly and randomly to legal provisions and processes at other levels. The political debate supporting extended children's rights rather refers to general observations, to the specific regional context, and constitutional provisions in other Länder. At least with regard to this issue, the multi-level system did not systematically impact on constitutional politics in the Länder. It rather can be understood as an opportunity structure providing parties with multiple realms in which they can pursue their goals. Thus the study shows that federal and regional party strategies are key factors in explaining policy diffusion in multilevel systems.