Photograph after black-and-white photograph of the D-Day landings have appeared on our television screens, in print and on countless internet sites in recent days. Scanning the faces I realised I was doing more than absorbing the grim reality of the largest seaborne invasion in history and the turning of the tide of the Second World War. I was looking for my father.
He was at Dunkirk, I knew that. He had been with his regiment, the Royal Engineers. But he was later attached to the Commandos and had been involved in actions behind enemy lines about which he remained stonily silent until the day he died. Towards the end of the war he had been posted to Palestine, for we had his olive-wood photo album. But in between, I had long wondered, did he take part in the Normandy landings. I was just 16 when he died, and never found a mood in which he could be enticed to break that silence.
There was a moral ambiguity to killing which my Dad, a good Catholic, was not prepared to cheapen to satisfy the curiosity of a child. But there was nothing ambiguous about the cause for which the men of his generation fought, nor about the courage with which they steeled themselves to the frightening fight.
Last week his comrades-in-arms did speak, and it was with the venerable understatement of a previous age which was all the more moving for its quiet modesty. "There was a job to be done." But the tears of the old men, the bewildered admiration of the great-grandsons they had brought with them for this last pilgrimage to Normandy, and the heartfelt handshakes of the middle-aged French women who grasped their hands in greeting, all of that spoke with eloquence. These were the men, as one older relative put it to me, who "were all that stood between us and the prospect of a Nazi tide which, if it swept us aside, would go on to conquer the whole world".
It is hard to imagine what cause might unite the present generation in such an enterprise today. And that is not just because the present is always more muddled than the past. The war against Hitler, his fascist ideology and his genocidal death camps had a great narrative of good versus evil. Its outline had a shocking clarity. In our post-modern epoch, we are constantly told, all narratives have equal validity. The phrases which fell from old men's lips on Friday – about camaraderie and esprit de corps – sound alien to modern ears.
Nazism was outlived by Communism but, with the fall of the Berlin Wall in 1989, American capitalism confidently pronounced The End of History. That reckoned without the tenacity of nationalism – which broke out like a virulent rash all across eastern Europe – and fundamentalist religion which quite shattered the old world order with the 9/11 terrorist attacks on New York and Washington in 2001.
Our wars since then have seemed a good deal more confusing. The self-righteousness of our invasion of Iraq has ended in a murderous sectarian quagmire. In Afghanistan we seemed uncertain of the purpose of our military engagement against the Taliban who had earlier been armed by the Americans in order to drive out the Russians. The war on terror ended up with the insupportable detention without trial of Guantanamo Bay. In Syria we have backed the opposition to Assad only to find that it includes al-Qa'ida affiliates whom many fear as a greater evil.
There is one clear grand narrative. Next year China will overtake the United States as the world's biggest economy. But in most other respects the picture is fractured. The European Union was set up as a "never again" bulwark against a war in Europe but, for some, the grand European project has begun to lose traction, as the rising Ukip tide has shown. In its place the European Right is raising panic against what it calls "the Islamisation of Europe". France has banned head-scarves in state schools, Belgium the full veil, Switzerland minarets on mosques and there are campaigns in Norway against circumcision and halal food.
In none of this is there the kind of idealistic cause which inspired volunteers such as George Orwell to go off to Spain to join the International Brigade to fight fascist Franco – unless, of course, you count European jihadists going off to Syria, which is not the kind of idealism about which we really want to hear. Ukraine's fight against the insidious and unpredictable behaviour of its neighbour Russia inspires a vague and general hope for peace. But it inspires no nations, or volunteer individuals, to put their boots on the ground.
A year before the US entered the Second World War President Franklin D Roosevelt set out a vision of Four Freedoms to ensure world peace after the conflict. They included "a world-wide reduction of armaments to such a point… that no nation will be in a position to commit an act of physical aggression against any neighbour".
Barack Obama sounded a good deal less utopian on Friday when he advised our own age "whenever the world makes you cynical – stop and think of these men". Yet only the hard-hearted would not have felt emotion at the rheumy tears of those whose comrades gave their tomorrow for our today. But they were clear about what had to be done when faced with Hitler's tyranny. They fought for freedom. Today we are a lot less clear about what freedom means. And what we need to do about it.
Paul Vallely is visiting professor in public ethics at the University of Chester