All this week, celebrations for Victory in Europe Day are taking place in Britain, France and even in Germany. It was on May 8, 1945, when Nazi generals signed onto an unconditional surrender with the US and its allies. The international system of law and commerce that was built in the years after the war helped shape the global order in profound ways, but that system is now coming under strain. By questioning US alliances in the European Union and with NATO, the Trump administration is putting the old post-war international system to the test. The World’s Matthew Bell reports.