Przemyslaw Czarnek, the education minister, has rejected a proposal made by opposition leader Donald Tusk to change the Polish constitution in order to make it harder for Poland to leave the EU, saying there is "no need to add or change anything". Poland's EU membership has become the subject of widespread debate in the country owing to protracted disputes between Brussels and Warsaw, and comments by a leading member of Law and Justice (PiS), the dominant force in the ruling coalition, suggesting the country might have to quit the bloc.