Judicial policy-making is having an increasing impact on political domains traditionally guarded by national sovereignty. This paper examines how the European judiciary has expanded Community competences into the policy domains of welfare and immigration, followed by subsequent Europeanization, against the preferences of the member governments. It finds that the principle of proportionality constitutes a most powerful means for the European Court to strike the balance between supranational principles and national policy conditions and administrative discretion. While the Court has previously been cautious to apply the principle beyond economic law, it no longer treads as reluctantly, instead generally limiting the inner core of national policy control, i.e. the capacity of the national executive to detail, condition and administer national policies in almost all domains.