International politics today looks increasingly like a bonfire of agreements, norms and rules. The US — the anchor of the world order — is assaulting the global trading system, and has withdrawn from international agreements on climate change and Iran. China, the rising power, is building military bases across the South China Sea — in defiance of rulings by an international tribunal, and the wishes of its neighbours. Russia has annexed Crimea, part of a neighbouring country.

Both America and China are increasingly tempted to break free of the constraints of international agreements and to use their power to achieve their goals, unilaterally. Russia lacks the economic might of a great power. But it has the territorial expanse and the nuclear arsenal, and has made a mighty contribution to an atmosphere of growing international lawlessness.

All of this creates a dilemma for the world’s middle powers. Germany, France, Japan and Britain cannot flex their muscles like great powers. But they are international players, with global economic and security interests. They need a world with rules.