The Polish government is trying to oppose the re-election of Donald Tusk as European Council President.
Donald Tusk is Polish (former PM) and was leader of the opposition party. The current Polish government argues that Tusk has meddled in Polish domestic politics whilst holding his EU role. Since one of the roles of the European Council President is to build consensus between member countries, this is good evidence for a question that asks you to assess his role or effectiveness (Unit 4 EU Institutions).
Interestingly, since the election of the European Council President is via QMV, the opposition of the Poles is unlikely to be enough to prevent his re-election.