Razed to the ground by the Wehrmacht in 1944, Warsaw has never been easy terrain for the foreign minister of Germany.

As his convoy speeds through the Polish capital, Heiko Maas passes first the Soviet army war cemetery and then the memorial to the victims of the Warsaw uprising — potent reminders of the bloody price that German aggression has inflicted on Europe. At a press conference the next day, the foreign minister is asked about new Polish claims for war reparations. At a public debate an hour later, Mr Maas listens politely as his Polish counterpart lashes out at Berlin’s liberal refugee policy. On both occasions, he decides not to respond.

Being in charge of German foreign policy is a tough assignment these days — not just in Warsaw but in countries around the world. Over the past few years, Berlin has watched with growing despair as friends have turned into foes and old certainties have dissolved into doubt. A new breed of nationalist leader holds sway in capitals from Budapest and Warsaw to Rome and Washington, sounding a note of hostility and antagonism towards Berlin. For reasons both economic and political, Germany’s relationships with key powers such as China, Russia and Turkey are marked by growing tensions.