One fact about Syria’s tragedy helps to explain Europe’s migration crisis. An absolute majority of Syria’s 20 million people are now refugees, either within or without their country.Even the most war-torn lands seldom endure the displacement of more than 10 or 20 per cent of their people. In Syria, the proportion of citizens driven from their homes has risen above 50 per cent. Today, at least four million are living in refugee camps in neighbouring states; another 6.5 million are “internally displaced” within their homeland.So it is that Syria has endured every possible calamity since the onset of civil war in 2011. The strongest argument against Western intervention was always the simple cry: “You will make things worse.” Given the enormity of th