The Polish Constitutional Tribunal ruled on Oct. 7 that some of the European Union’s (EU) laws conflict with the country’s constitution and that national laws will have supremacy over those of the EU in areas where they clash. The decision of the tribunal was filed on a motion by Polish Prime Minister Mateusz Morawiecki, who…

WARSAW—Poland’s highest court ruled on Thursday that some parts of EU treaties are incompatible with the Polish constitution, challenging a pillar of European integration and sharply escalating a dispute between Brussels and Warsaw. The European Commission said the ruling raised serious concerns about the primacy of EU law, setting it on a full collision course…