Glenn often harkens back to September 11, 2001, as a pivotal day for the American spirit. When American Airlines Flight 11 hit the South Tower at 8:46 a.m. that sunny September morning in Manhattan, there was no question that September 11 would become one of the most consequential moments in American history. However, in that moment, the outcome of that day was yet to be determined.

How would September 11 be remembered in history textbooks? Would it be the beginning of the end of our Republic? Many thought so and for just reason. Our country was under attack. Planes hijacked by our enemy were headed towards the buildings that represented the institutions that comprise the fabric of our republic. If there was any day that called into question our nation's future, it was September 11.

New York City firefighters and a photojournalist work at Ground Zero after two hijacked planes crashed into the Twin TowersRon Agam / Stringer | Getty Images

But the American spirit had a different narrative in mind. Instead of caving to the narrative that the hijackers attempted to write, the American people rose to the occasion that duty beckoned. As Glenn wrote in an essay the day after the September 11 attacks, "Americans don't run from burning buildings. We run into them." And we did. Many remained there as their final burial place.

The American people rose to the occasion that duty beckoned.

As New York Governor Pataki remarked, "On that terrible day, a nation became neighbors." We weren't Democrats. We weren't Republicans. On that day, we were Americans. We chose to write a different narrative in the history books following 9/11, one of resilience, bravery, brotherhood, and the triumph of the American spirit.

As Glenn so poignantly wrote on September 12th:

The spirit of our parents and our grandparents isn't from some foreign place. It hasn't died out. It's a flame that flickers in all Americans.

And that flickering light turned into a roaring fire on that pivotal day, one that not even the fires in the World Trade Centers, the Pentagon, or the empty field in Shanksville, Pennsylvania could consume.

We chose to write a different narrative in the history books following 9/11, one of resilience, bravery, brotherhood, and the triumph of the American spirit.

But can we say the same about the American people today? Do we still carry the flickering flame of the American spirit that has been passed down to us from generations past? As Glenn reflected today, 22 years after penning those words, he isn't so sure. And I'm not either.

A candlelight vigil for the victims of the World Trade Center terrorist attack is held at Union Square in New York City.Evan Agostini / Contributor | Getty Images

The same American spirit that we relied upon to pull us through September 11 seems to be a waning flame in a torch that few are clinging to. We are increasingly losing sight of what it means to be an American. Common principles that we traditionally shared across party lines are now being vehemently contested, both by the ruling class and in the public square. This is not the same America that triumphed over September 11.

We are increasingly losing sight of what it means to be an American.

This raises the troubling question: Could we endure another attack of a similar magnitude? Would the triumph of the American spirit dictate the narrative of that day, or would a foreign enemy steal the pen from liberty's fingers? These are the tough questions we must wrestle with in our pivotal moment as a nation.

But these questions aren't devoid of hope. There is still time to recall those timeless principles that transcended party lines on September 11 and united us as Americans. There is still time to nurse the waning flame for those who are committed to holding liberty's torch. There is still time to view our political opponents as, in the words of Pataki, "neighbors," whose livelihood and future depend on the survival of our great nation.

There is still time to recall those timeless principles that transcended party lines on September 11.

But that window is short. We must strive towards unity now if our nation hopes to, as Lincoln said in his own time of division, "endure."

As Glenn wrote in that essay on September 12, 2001, we must be, "awake and out of bed, for there is much work to do. [...] Our flame has not burned out. It had just been dimmed while we were asleep."

Acouple cary the American flag down a lower-Manhattan street a week after the September 11 attacksRichard Baker / Contributor | Getty Images

Flames cannot flicker forever. If they are not nursed, they will flicker out, leaving darkness in its wake. It's time to wake up. We must be attentive and awake, nursing the remnant of liberty's flame until it is blazing like it did 22 years ago today. We cannot let it die on our watch. Too many people have sacrificed too much for us to drop the torch.