Different theories have been developed, mainly in the context of the United States, to explain judicial decision-making. In this respect, there is an important ongoing debate over whether judges are guided by the law or by personal ideology. The analysis of the decision-making in the Polish Constitutional Tribunal seems to support the existence of some party alignment. It is to say that judicial behavior is influenced by the ideology, either because judges’ preferences coincide with the interests of a specific party or because the judges are incentivized to show their loyalty to a party. Party alignment exists but subject to institutional influences. These results are in line with previous findings for other constitutional courts in Europe.