Look at Syria and you can see all the elements that have led to world wars

This crisis is already displaying the familiar preliminaries to a reckless conflict. Hysterical language cavorts with the machinery of militarism. It seeks reasons for violence, not for its avoidance. Thus there was no reason for Britain to go to war with Iraq in 2003, beyond a sabre-rattling competition between Tony Blair and America’s George Bush. Nor back in history was there a reason for Germany and France to fight in 1870. There was no reason for war in 1914, beyond the murder of an archduke in Serbia. As AJP Taylor said of 1914: “Nowhere was there a conscious determination to provoke a war. Statesmen miscalculated [and] became prisoners of their own weapons. The great armies, accumulated to provide security and preserve the peace, carried the nations to war by their own weight.” I wonder what Taylor would have said of Trump’s “Get ready Russia” tweet.

Most wars nowadays follow a triggering of often casual alliances and obligations, and from the absence of any potent forum – or even “hotline” between leaders – through which disagreements and minor disputes might be resolved. Peace in Europe was roughly sustained for 50 years through the councils of the 1815 Congress of Vienna. Then it collapsed as if from exhaustion. The dread prospect now is that the post-1945 cold war settlement, roughly overseen by the United Nations, has outlived its usefulness.