On his last official visit to Berlin in November 2016, Barack Obama paid glowing tribute to Angela Merkel, the German chancellor. “As I reflect back over the past eight years, I could not ask for a steadier and more reliable partner on the world stage,” the outgoing US president said. Ms Merkel spoke no less warmly of her transatlantic friend and ally.

Six months later, it was a different, more disturbing story. “The times when we could completely rely on others are, to an extent, over,” Ms Merkel told an election rally in Munich, in an unmistakable reference to Donald Trump’s jaundiced view of the values-backed western order that had flourished for seven decades under US leadership.

As Ms Merkel announced plans to step down as leader of her Christian Democratic Union party and then as chancellor in 2021, Europe, the western alliance and liberal democracy appear to be under just as much strain as 18 months ago, and much more than when she rose to political prominence at the turn of the millennium.