The European Court of Justice (ECJ) released a statement Friday condemning a German court’s challenge of the ECJ’s judicial supremacy. “In order to ensure that EU law is applied uniformly,” says the statement, “the Court of Justice alone⁠—which was created for that purpose by the Member States⁠—has jurisdiction to rule that an act of an EU institution is contrary to EU law.”

On May 5, Germany’s Federal Constitutional Court challenged the legality of the EU’s Public Sector Purchase Programme (PSPP), an economic policy that institutes large-sum bond purchases from the European Central Bank (ECB). The ruling declared the ECB’s policy Ultra Vires, or having been passed without Germany’s legal overview, and claimed that the PSPP was in violation of agreements reached in the Treaty on the European Union.

In particular, the German decision takes issue with the PSPP’s purchase of more than €2.2 trillion in public debt. The PSPP, passed partly in response to the Greek Debt Crisis of 2015, requires economically-stronger EU member states to buy back public debt from economically-weaker states, often without the buyers’ consent.

In the past, Danish and Czech court decisions have found ECJ rulings to be Ultra Vires, but this instance is the first in which a German constitutional court has challenged EU judicial supremacy.

“Divergences between courts of the Member States as to the validity of such acts would indeed be liable to place in jeopardy the unity of the EU legal order and to detract from legal certainty,” concludes the ECJ statement. “National courts are required to ensure that EU law takes full effect.”

The ECJ has noted that they will make no further statement on this matter.