Citizenship policy in Germany has been highly contested, particularly regarding dual citizenship. Nearly 25 years after the failed attempt of the SPD and Bündnis 90/Die Grünen coalition to fully adopt dual citizenship, the principle of avoiding multiple citizenship was abolished with the Citizenship Modernisation Act of 2024. This paper examines the long-term policy change using the Advocacy Coalition Framework (ACF), which is well-suited for analysing both policy stability and change over extended periods, especially with regard to contested policy issues. The policy change took place in three central stages: the introduction of ius soli with temporary limited dual citizenship (1999), the abolition of this limitation (2014), and the full acceptance of dual citizenship (2024). Key factors explaining policy change and stability between 1999 and 2024 are strongly linked to the federal system. These are the shifts in power at federal and Länder level as well as relatively stable parameters lying outside the policy subsystem and the related and changing coalition opportunity structures due to the federalism reform of 2006. Further aspects are public opinion, a brokered compromise, changing beliefs as well as empirical issues concerning the seriousness and causes of the policy problem.

Martin Weinmann, Advocacy Coalitions, Power and Opportunities: Policy Change in Germany’s Dual Citizenship Policy Subsystem, German Politics, 2026.