Fifteen years ago today, on a morning bright and clear, the world as we knew it came to an end. For generations, America’s rise from rural isolation to global power had been a story of aspiration and accomplishment. In a world of feuding global powers and empires, our land was something new in the history of man. A nation of the people, by the people and for the people. Somehow different and a break from an old world marked by kings, queens and dictators.

Our choice to be the land of the free seemed ratified as blessed by destiny. Our population grew one hundred fold and our dominion stretched across a continent and beyond. For almost 200 years America acted upon the world, the world did not act upon America.

We avoided the global conflagration of the Second World War until our territorial outpost at Pearl Harbor was attacked. From that moment forward, America mobilized and once again acted upon the world, saving the world from fascism, facing down communism, restoring hope and rebuilding a shattered world. We even went to the moon.

All was upward. America’s story was one of challenges made and challenges met. Generations of Americans grew up with the surety that they were safe from the storms that swept the old world. There was safety and security on our shores, in our homes.

But on Sept. 11, 2001, that era ended. In a terrible instant we all understood that, for us, the world had changed. The very symbols of our strength were shaken. It was a strike from the shadows. An insidious new foe of whom we knew little and whose methods were the stuff of nightmares.

And so we rallied, and girded for war. As in the past, this is what one does when under attack. We mobilized at home, building a security structure to protect us from future foreign invaders. We doubled the border patrol, put thousands of air marshals in our skies, spent billions on border walls, strengthened law enforcement and tripled the budget for the FBI.

We responded to the attacks that came from the hellscape that was Afghanistan by projecting massive military force on the other side of the planet. We unleashed preventive war in a bid to “transform the Middle East.” All in the hope that by our actions we might restore a world in which America was safe and secure from terrorist threat. Safe from the kind of shock we felt on 9/11

Where are we now?

The national unity and sense of purpose we felt in the days after 9/11 has faded. Our bid to tame a turbulent world was lost in the deserts of the Middle East. Quick victories faded in to the prospect of endless conflict. And the war on terror turned into a long twilight struggle against unseen enemies. It tore at the fabric of our Constitution and has tested the very notion of who we are as a people.

The trillions of dollars spent, the thousands of lives lost in our quest for security have left us seemingly no more secure against terrorist attack than we were on that autumn morning.

And yet we are better prepared. We are more likely to prevent such future outrages. We can respond to and recover from terrorist attacks better than we could have 15 years ago.

Since 9/11, our military has dealt a devastating blow against al-Qaida, shattering their command and control network. They have failed to carry out another spectacular, coordinated attack against the United States.

Osama Bin Ladin lies dead in a watery grave.

Some say that the future is dark, that the rise of ISIS foreshadows a world of dystopian disorder. But we have learned in these past years. And rather than lash out in righteous fury, the armed forces of the United States, guided by an intelligence community of unrivaled capabilities and supported by a diplomatic corps that has built a global alliance, have rolled back the latest threat.

Since its rise in 2014, ISIS, the latest manifestation of violent extremism in the Middle East, has suffered defeat after defeat and lost close to half of its territory.

We are better able to prevent terrorist attacks at home than before 9/11. Law enforcement works together in unprecedented coordination and have prevented many plots from moving past the planning stage. First responders are better prepared and equipped than at any time in American history to meet the challenges presented by domestic terrorism.

The real meaning of 9/11 will be determined by each of us. The real test comes down to how we answer the question, do we allow ourselves to see a dark world defined by the lunatic acts of a tiny and twisted group of castoffs, or do we choose to make our own destiny? Do we build a future informed by the hard realities of life, but inspired by the fact that we can meet and master the challenges before — as American always have, and always will.

Scott Bates, former president of the Center for National Policy and currently chairman of the Board of Directors of the Connecticut Port Authority, lives in Stonington. He will speak about 9/11 today at 5 p.m. at the La Grua Center, 32 Water St., Stonington.