When the Venice Biennale opens to the public next April, exhibitions at the 29 national pavilions are expected to blur cultural boundaries more than ever before. Curators say the 60th iteration of the world’s largest contemporary art event, entitled “Foreigners Everywhere”, will be a celebration of migration and non-belonging. The Polish pavilion, however, will play to a different tune – one straight out of the playbook of the nationalist-populist Law and Justice party (PiS) that has ruled the country since 2015. After the recent election, it is expected the PiS will be out of office by the time the Biennale...