It was a day that did not end.

It went on for days, it went on for weeks, it went on for years. But then you look up and somehow, 20 years have gone, and you realize with a start that you can't recall the last time you thought of Sept. 11, 2001. "We'll go forward from this moment," I wrote. And we did. And we have. So much so that maybe the events of that day begin to feel a little distant.

So it's shocking how easily it all comes back.

Indeed, to review the old footage is to return to that morning with visceral urgency, two decades stripping away like varnish, like nothing. Suddenly it is once again that fateful Tuesday morning, and there is a pit in your stomach, a tension in your jaw as two iconic New York towers are impaled by jetliners, as fire blooms like some death flower, as great mountains of smoke float over the skyline, as dust-caked people stagger about like confused ghosts, as first word comes of an explosion at the Pentagon, as a plane disappears from radar over Pennsylvania, as TV news anchors struggle for words to comprehend the incomprehensible, as your heart breaks, and breaks.

All of it comes right back. Just as if it never really left.

It felt like we had stepped off the edge of the world. Remember that? A band of Muslim extremists had bloodied us — us, the most powerful nation on Earth. We were in shock.

The magnitude of that day's losses would be tallied in a currency of vaporized lives, shifting political gravity, vast acres of twisted metal and pulverized debris. To look back from a vantage point of two decades, however, is to realize even that grim tally is incomplete.

Because for all that we lost that day, perhaps the most important thing we lost was ourselves.

Before that day, the idea of America jailing citizens without charges or trial would have been unthinkable.

Before that day, the idea of America rationalizing torture would have been inconceivable.

Before that day, the idea of America disappearing its enemies would have been unimaginable.

Before that day, the idea of America keeping a secret list that barred you from flying would have been unbelievable.

Before that day, the idea of America spending 20 years and an estimated $6.4 trillion and 801,000 lives on endless wars without clear mission parameters or exit strategies would have been unacceptable.

And before that day, the idea of America electing Donald Trump as its president would have been downright laughable.

But that day tapped a deep seam of xenophobia and fear in the American psyche, making possible the election of a man who campaigned on "a total and complete shutdown of Muslims entering the United States" — even as white nationalist terror cells were training in the woods. Before Sept. 11, Trump's presidency — and the myriad catastrophes proceeding from it — would have seemed the stuff of some bizarre, outlandish fiction.

But we have become a nation of truths stranger than fiction, a nation where satire must run to keep up with reality. As we go forward from this moment, we find ourselves contending for the very soul of America — something none of us could have imagined 20 years ago. Which is why it must be said, tragically, that the terrorists succeeded beyond their dreams in inflicting damage on this country.

We've long calculated in a currency of lives, politics and pain what they did to us. But a true reckoning demands an additional tally:

Namely, of what we have done to ourselves.

Contact Leonard Pitts Jr. of the Miami Herald via email at lpitts@miamiherald.com.