Free movement is a foundational right of EU citizens. When expelling a citizen of another member state on the grounds of public security (the other possible grounds are public health and public policy), the expelling state must show that the citizen represents ‘a genuine, present and sufficiently serious threat affecting one of the fundamental interests of society’. This is, or should be, a very high bar. A Polish citizen, Kasia Wlaszczyk, and two Irish citizens, Roberta Murray and Shane O’Brien, currently living in Berlin, have been ordered to leave Germany by 21 April or be deported, along with Cooper Longbottom, an American holding a student visa. All are active in the Palestine solidarity movement. None has any criminal convictions.