The recent devastating earthquake north of Rome is another reminder of how tenuously we live at the mercy of forces greater than ourselves.

But not all of earth’s dislocations are natural. Rancorous fault lines in the political, economic, and social bedrock of our democracy are slowly pulling us apart. If the pressure continues to build, our country could be shaken to its very core.

There have been times in America’s history when tragedy united us as a people. 9/11 was one of them. Since then, however, this bond has been unraveling, strung out by violence, lawlessness, and incendiary public discourse.  During this contentious presidential campaign, the rift within our country has widened further.

This year we will mark a 9/11 milestone anniversary. Fifteen years ago, on a bright and beautiful morning, the lives of almost 3,000 innocent and unsuspecting victims ended in scenes of horror. Not a single shot was fired during the worst terrorist attack on American soil. It took only nineteen box-cutter-wielding savages to do the unthinkable.

All these years later, their radicalized brethren continue the mission of delivering death to the infidel. Sadly, the number of terrorist acts has risen. While individual atrocities may involve fewer victims, the steady drip-drip in the pipeline of hate has heightened our fears, and the world now holds its collective breath in expectation of another tragedy on the scale of 9/11. Some people have resigned themselves to calling this “the new normal.” But there is really nothing “normal” about it.

Less than a year before the Twin Towers toppled, I was on the observation deck of the taller tower, looking out over the hazy landscape of downtown Manhattan. At 107 floors above street level, the winds were howling and the rarefied air was bitter cold. The sheer height of the Twin Towers’ created a weather pattern all its own, and on that wintry day, few sightseers ventured outside the comfort of the Windows on the World restaurant.  

A month after 9/11, I was back for another visit to a more somber city. Grief, grime, and disbelief hung over it like a soiled shroud. In the Queens community of my childhood, there was hardly a neighbor who did not have some unbearably sad connection with the tragedy. And clear across our shocked nation, people knew people or knew people who knew people who had lost their lives or miraculously survived.

The connections spread like tentacles of sorrow. The best friend of my best friend’s daughter had lost her husband when the first plane struck. Ironically, he did not even work at the World Trade Center. His investment firm needed a representative to attend a business breakfast scheduled there on 9/11. The night before that fateful event, he had flipped a coin with another colleague to see who would go. In his final cell phone call to his wife, he optimistically reported that help was on its way.

A lot can happen in fifteen years. A child trotting home from kindergarten morphs into an adult looking forward to graduating from college. An empty hole at Ground Zero finally fills -- if contentiously --and an impressive building of structural beauty defiantly rises as a symbol of America’s resilience.

But some things have resisted change. Even as two tall buildings were replaced by one, so has one terrorist nemesis been replaced by a succession of others, all with the same objective of destroying our way of life.

Those in seats of power assure us that since 9/11 Americans have been relatively safe. They pride themselves -- and rightly so -- that another unthinkable tragedy of such enormous proportions has been prevented on their watch. Still, they remind us that, despite our sophisticated methods of vigilance, the terror-driven problems remain dangerously “nuanced.” In place of the big terrorist rat that boldly hitched a ride on our domestic airlines, we now confront radicalized martyrs who chew away like mice at the fabric of our nation’s security: Boston, San Bernardino, Orlando, Fort Hood, Chapel Hill, Chattanooga, and others.

For that reason, Americans do not feel as safe as our leaders suggest. The majority of us say that we are, in fact, less safe than we were before 9/11. And the fact that we are also less united as a people suggests that these two realities are somehow related.

Our enemies are ever alert to signs of America’s weakness. And it is not hard to spot them in our current cultural milieu. The breakdown of civility takes many forms, each of which plays into the desires of those who would destroy us. A divided country without law and order is far more easily subdued.

That is why there is a danger in seeing only the shackles that divide us while ignoring the common bonds that forge us into one nation under God. When a highly paid NFL quarterback -- wearing socks with a pattern of pigs in police gear -- garners sympathy for refusing to stand during our national anthem, it sends a signal to the rest of the world.

Colin Kaepernick’s taking a knee is not as incendiary as, say “bombs bursting in air,” but it tends to dominate the dialogue at the expense of greater concerns. How many such incidents will it take before a house divided against itself cannot stand?

From the inception of our country, Americans have been admonished not to forget the historical events that steeled our communal will. “Let’s Remember Pearl Harbor” was a popular song during WWII. Before that there were mottoes like “Remember the Alamo” and “Remember the Maine. They recalled the troubling times during which we were called upon to put aside our differences and come together as a people.

 9/11 is one such day to remember. Yet within a mere fifteen years, its memory seems to have largely faded from national consciousness. Maybe our preference for living in the present and looking to the future leaves little room to replay the past.

Still, there will be plenty of replays of the past on 9/11/2016. On our television sets and other electronic devices, the doomed planes will once again collide with the towers and burst into giant balls of flame.  The majestic glass monoliths will once more sink incredulously to their knees. The billowing clouds of dust and debris will envelop ghostly survivors fleeing the inferno. In commemoration, there will be impressive ceremonies at Ground Zero, Shanksville, and the Pentagon in honor of the brave and the terrified who perished.

Is it too much to hope that this year’s milestone might pull our citizens together by the heartstrings? Is it naïve to suppose that once again the mutual mourning of this great tragedy could help to unite and heal us?  Or has the friction of our ideological tectonic plates already displaced the concept of e pluribus unum.