My father's service on D-Day 80 years ago – the horror, the sheer hell of crossing the sand that morning – was all something of an abstraction to me. That changed when I saw "Saving Private Ryan," Steven Spielberg’s masterful, shocking film depicting the horror of the Omaha Beach landings and the grueling combat that followed. 

Suddenly, I could picture it: At just 18 years old, my dad landed with the first wave at Utah Beach and fought for the next month, until a German bullet pierced his helmet, entering his skull and nearly killing him. 

I called my father – by that point retired from a half-century career in dairy distribution – from the lobby of the movie theater, enquiring how he had done it: How did he leave that landing craft facing imminent death? His simple answer was, "It was my duty, son."  

Members of an American landing unit help their comrades ashore during the Normandy invasion. (Louis Weintraub/Pool Photo via AP)

Patriotic values had always been a part of our family. But the notion of duty – so calm and devoid of self-interest – seemed almost unreal. 

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I pressed him further, and he went on: "I wasn't going to let down the guy to my right, or the guy to my left, or Gen. Roosevelt in the boat ahead of me." His conception of duty, it was clear, consisted of an unwavering commitment to service above self. No exceptions. 

It was service and sacrifice like my dad’s that led to his generation rightly being labeled "the greatest." But they are not the only generation who can embody this ideal. In fact, a renewed commitment to service above self is an antidote to one of the greatest troubles of our present age: how to bring the lessons of the past forward with us, and learn from them. 

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Americans today are more disconnected from our history, more dismissive of its lessons and less appreciative of its gifts than ever. The effects are grave: we’ve become more fragmented, entitled and blind to the risks of a world run amok.   

A key effect of pursuing service above self, however, is an appreciation of the service of others – and the service of those who came before. This gratitude is deeper than sentimentality: it allows us to understand the toll of war and the value of peace. It urges us to connect the past with the present and take part in the ongoing battle between freedom and tyranny. 

Gratitude also helps weave together the fabric of our nation. Though my family came to America from England following World War I, I'm indebted to centuries of Americans who served this country to make it prosperous and free, the greatest the world had ever known. 

American medics render first aid to troops wounded in the initial landings on Utah Beach, France, June 6, 1944. (PhotoQuest/Getty Images)

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I often think about the scores of patriots who fell in the fields surrounding my home in Pennsylvania during George Washington's defeat at the Battle of Brandywine in 1777. What were they thinking of their sacrifice and the generations to follow? 

One might grant that D-Day and other great sacrifices were laudable, but complain in the next breath that the world is much more complicated today. In a world of murkier morality, they say, such selfless devotion is no longer the model to follow. 

To the contrary, murky areas of morality are not new. How could one better describe the circumstances of the wounded young men of the German Wehrmacht, whom my father guarded as prisoners yet cared for and bonded with? 

Gen. Dwight D. Eisenhower talks with American paratroopers on the evening of June 5, 1944, as they prepared for the Invasion of Normandy, in Berkshire, England, June 5, 1944. (Underwood Archives/Getty Images)

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The difference between their situation and my dad's, of course, was the principles of the nation for which they were fighting. 

America is and has always been imperfect, but that's all the more reason to roll up our sleeves and get to work. Preserving, improving and sharing our culture of freedom and democracy requires immense sacrifice, great and small. 

The tangible threats America faces, moreover, are momentous. As secretary of the Navy, I had a front-row seat to assess the military capabilities of China’s People's Liberation Army and Navy. Simply put, we've never been in a situation where a near peer competitor is as strong and well-equipped. 

American soldiers leave a landing craft under fire, on D-Day, June 6, 1944. (Roger Viollet via Getty Images)

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On anniversaries like this, when you walk through the impeccable military cemeteries cared for by the American Battle Monuments Commission, it's natural to wonder if America is capable of that depth of service and devotion today. I have no doubt, though, that our younger generations are capable. The young troops with whom I had the honor to serve alongside in Iraq, displayed the resilience of their predecessors daily. 

But before it comes time to put aside internecine quarrels and face a common enemy, I hope Americans remember this: the past matters. The story of D-Day is the story of you and the nation you're living in. As such it is always the time to do your duty and put service above self. 

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