I am hardly alone in remembering exactly where I was on the morning of September 11, 2001.

Walking into the government building where I worked, I remarked to a coworker about what a beautiful, clear September day it was. Twenty-five years later, that ordinary observation remains tied to an extraordinary day.

I was preparing to teach one of the most complicated classes my agency offered and was meeting with the education specialist when a manager peeked into the room. A plane had hit one of the World Trade Center towers, she told us.

A few minutes later, she returned. A second plane had struck the other tower.

We looked at each other. We knew what that meant.

Then came word that a plane had hit the Pentagon. The question now was: What would happen next?

Shortly afterward, our office closed, and we were sent home. I watched the news coverage while my wife worked at her desk at home.

We would also learn about United Airlines Flight 93, which crashed near Shanksville, Pennsylvania, after passengers and crew fought back against the hijackers. Their actions prevented the plane from reaching its intended target in Washington.

The attacks killed 2,977 people in New York, at the Pentagon and aboard Flight 93. Behind that number were individual lives, families and futures.

I remember telling a coworker that day that my twin daughters, very young at the time, would grow up in a different world from the one I had known.

My generation had lived through the tensions and frightening moments of the Cold War. We knew something about fear and uncertainty. But this felt different: commercial airliners turned into weapons, ordinary workplaces turned into targets, and no clear sense of where the danger might end.

Pearl Harbor offered a historical reference point for the shock of an attack on our country. When Japanese forces attacked on December 7, 1941, Hawaii was a U.S. territory, not yet a state. That distinction did not make the attack any less an attack on America.

In the aftermath of September 11, Americans responded with extraordinary generosity and courage. Many were inspired to join the armed forces.

Others found different ways to help.

I recall speaking with a nurse who had been working in Florida. She told her bosses she was going to New York to help. She did not wait for permission; she packed up and left.

Later, she shared harrowing accounts of what she encountered at the World Trade Center site—details I will not repeat here. Her story has stayed with me as a reminder of what people were willing to give, and what helping could cost them.

The suffering did not end when the immediate rescue and recovery work was over. Responders and survivors continue to need care for physical and mental health conditions related to the attacks and their aftermath.

As a nation, I believe we did some things very right after September 11 and other things very wrong. Historians and political scientists will continue to examine those decisions. Each of us can weigh that record as well.

My hope, twenty-five years later, is that we approach the threats we face with sound judgment. America has enemies. Protecting people requires resolve, reliable information and a willingness to consider the consequences of our decisions.

We should ask whether a response will make us safer, what it will demand of those asked to carry it out, and what burdens it may leave for the next generation.

When I think back to that clear September morning, I remember my daughters and the different world I feared they would inherit. That concern still shapes how I think about our country’s choices.

We owe remembrance to those killed, compassion to those still suffering, and care to those who served. We also owe future generations our best judgment.

This is a difficult world. Meeting its dangers requires courage—and the wisdom to decide how that courage is used.