Coordination in the Core Executive under Separated Party and Government Leadership: Evidence from Poland

In parliamentary systems, the leader of the main governing party does not always hold the office of prime minister. This article examines how this configuration reshapes coordination within the core executive. Drawing on 10 in-depth interviews with former members of government and senior officials, documentary evidence, and theory-guided process tracing of the Polish Deal tax reform, the article examines the Polish core executive between 2015 and 2023. The findings show that formal coordination mechanisms continued to handle routine matters and support implementation, while final arbitration on politically salient issues shifted towards party-government arenas involving the party leader. The prime minister responded by selectively recentering administrative control around the Chancellery of the Prime Minister. Separated leadership therefore did not eliminate formal hierarchy. Instead, it separated the locus of political arbitration from the centre of administrative direction, causing the effective centre of coordination to shift across successive phases of the policy process.