For the first time since being a resident head in the dorms at the University of Chicago a few years ago, I’m spending September 11 in the milieu of a university campus. In thinking about the incoming class who in a fortnight will begin college life here at Oxford, it occurred to me that most of them were just infants when the 9/11 terrorists perpetrated their evil acts. Some were not yet even born. None have any living memory of the attacks.

Drew Griffin, our new(ish) managing editor, has been asking people whether, and if so why, 9/11 still matters. Why do we need to remember that day? It’s a question worth reflecting on, in part because I fear that, while many current college students did not live through it on that terrible day, many of those who did are no better positioned to recall what that day was really like. They have forgotten or have chosen to forget. My doctoral supervisor, Jean Bethke Elshtain, would have said that forgetting 9/11 is a terrible mistake. “We shouldn’t,” she would have asserted. “It was just as bad as we remember it.”

So what, then, is important to recall, particularly for Christians, about that terrible, god-awful day? Here are a few, but by no means comprehensive, considerations.

1. There is a place for anger in the Christian life. Whether we take it on the advice of Aristotle or Thomas Aquinas, anger is not necessarily evil. It is the perversion of anger that must be avoided. But this can occur in both directions. One can be excessively angry, disproportionate to the offense. But in just the same way, one can be insufficiently angry. Aquinas reminds us that we ought, always, to be like God in seeking justice and to love the good. Anger is appropriate when some injustice destroys the good. One can be angry at the rights things, in the right degree, at the right time, for the right purpose, and in the right way.

On 9/11, our individual and collective feelings of anger were appropriate to the horror. Innocent people were murdered without cause. Planes full of our neighbors were weaponized in an unprovoked act of criminal war. We must never forget the anger of seeing our brothers and sisters jump to their deaths from burning buildings to escape the flames. We are made in the image of a God who overturns tables. Sometimes anger is the appropriate spark needed to set ablaze the tinder of our passions and to steel our courage for the fight ahead.

2. Sometimes tables need to be flipped. Taking seriously the dominical command to love our neighbor, Christian realists began from the very beginning to articulate what would come to be known as the just war tradition. Simply stated, wars can be justifiably fought in the last resort when a sovereign authority, over whom there is no one greater charged with the care of the political community, determines that nothing but proportionate and discriminate force will protect the innocent, take back what has been unjustly taken, or punish evil.

The just warrior does not prefer violence to non-violence. He merely accepts that there are times when violence is already being committed and the only question left is whether violence will be committed only against the innocent or whether counter-force will be used to rescue the innocent.

3. To remember 9/11 and to respond appropriately is a means to help vindicate the victims. Appropriate anger and the restoration of justice is an expression of the recognition of the value of what was lost. To not remember 9/11, or to not respond appropriately, is to diminish or deny the worth of those whose lives were untimely ripped from life.

Similarly, to remember 9/11 is to recognize the value of heroism. Many might have thought there were no more heroes in the world. That September day proved them wrong. There are those who charge up weakening stairwells to try and rescue the trapped; there are those who fight back to prevent worse from happening; there are those who deploy and take the fight to the enemy; and there are those who let their loved ones go to war on our behalf. That day brought back our belief in the old virtues. It brought back our recognition of our need for them as well.

4. September 11 reminded us of the importance of getting the facts straight. If we get our description of events wrong, we are bound to get our ethics wrong as well. Most people know what we mean in everyday life when we call something evil. Back then, Pope John Paul II described the evil attacks as an “unspeakable horror,” and people everywhere nodded their heads. We knew, we knew, his words were fitting. Though, perhaps not all of us knew.

Too many people, with far too many Christians among them, equivocated in the moment. They found themselves unable, or unwilling, to distinguish between a terrorist and a just warrior, to discriminate between murder and legitimate acts of justified war, or to call evil what it is. The increasingly maudlin understanding of love that has hamstrung much of the church’s ability to deal effectively—and justly—with evil has left our pews—and the wider public—with a sentimentalized understanding of the moral life. We offer the murderous mercy at the expense of their victims.

5. After those buildings fell, Elshtain famously turned to a friend and said, “Now we are reminded what governments are for.” Drawing from a tradition that runs through Paul’s letter to the Roman church, Elshtain reminded us that the primary purpose of human government is to protect the goods of justice, order, and peace of the political community. In a world in which neighbor preys upon neighbor, these goods are essential for any other good—such as health or life—to endure with any certainty.

Of course, goods are not protected by mandates alone. Just like a family must budget for and procure what is essential to its ability to flourish, the state must pay first for those things essential to the flourishing of the political community. When it comes to military budgets, too many Christians blather about false choices between “bread or bombs.” Undoubtedly, a part of the terrible costs of evil in the world is the waste it requires. Every time we buy keys or locks or security cameras or police cars or jails or any of other the innumerable material objects we purchase because of our need to manage human evil, we are reminded of the enormous monetary costs of sin. Nevertheless, such costs must be paid in order to prevent the worst from happening. Happily, America has the economic strength to both feed the poor and to protect them as well. There are no guarantees, of course. The 9/11 terrorists, despite our own comparative strength, still managed to punch above their weight and deal us a real blow. But it was not an existential threat, and our strength has certainly prevented worse from happening.

6. We must practice constant vigilance. The terrorist threat against America did not materialize suddenly on September 11. Some have long meant us great harm. From the bombing of the Marine barracks in Lebanon in 1983, to the Achille Lauro hijacking in 1985, to the attack on the World Trade Center in 1993, to hits on overseas American installations in 1995, 1996, and 1998, and to the strike on the USS Cole in 2000, America has been at war with terrorists for longer than we seemed prepared to acknowledge, and we were ill-prepared to respond.

Vigilance does not mean keeping a wary eye on the world from battlements along our border. It is in America’s own best interests to take a leading role in preserving and expanding the liberal order throughout the world. Justice, order, and peace abroad act as the outer perimeter of American security. When liberal norms shape the character of the international sphere, American safety and prosperity are most strongly assured. America is still the leading power in the world. While imperfect, no plausible alternative has been found to replace American leadership. If America does not do her part, other states will not do theirs—the twentieth century proved this.

In summary, September 11, 2001, reminded us of some basic theological truths. Made in the image of our Creator, humankind was made to exercise dominion—providential care—over creation. In a similar way, human government was created to care for those under its specific dominion. This was necessary because of the reality of the fall. Holding our role as image bearers in contempt, human beings abandoned the mandate for responsible dominion in favor of a self-centered lust for domination and a will to power. In more extreme cases, instead of loving their neighbors, some have chosen to prey upon them. Against such aggressors, human government comes to the fore to protect the innocent, requite injustice, and punish evil in order to maintain the political goods of order, justice, and peace. In the face of an intransigent enemy posing a sufficiently grave risk, war is sometimes right. On such occasions, pacifism is a dereliction of Christian responsibility and charity.

Finally, however great the responsibility of human government is, it is always only penultimate. God, not humanity, has the ultimate responsibility for history. Because of the limits of our knowledge, ability to judge, and the modest abilities within our powers, the Christian realist accepts that there is only so much we can do. Sometimes we must be content to do no harm, to prevent the worst, and to help where we can.

As those eager undergraduates come to campus, these are some of the things I hope they learn about September 11. These are some of the things that I hope the rest of us never forget. There is a price to forgetting.

And so we must remember so that we are never reminded again.

Marc LiVecche is the executive editor of Providence. He is currently living in Oxford, where he is the McDonald Visiting Scholar at the McDonald Centre, Christ Church College, Oxford University.

Photo Credit: A North Dakota Air Guard F-16 of the 119th Fighter Wing on a combat air patrol over the burning Pentagon on September 11, 2001, after the hijacked Flight 77 crashed into it. By Gil Cohen, National Guard Heritage Painting, via Wikimedia Commons.

Launched from bases all over the United States, Air National Guard fighters and tankers moved quickly to protect America from further attacks on September 11, 2001. That morning, 19 terrorists employed four hijacked airliners to destroy the World Trade Center in New York City and severely damage one section of the Pentagon. The attacks, which were executed by a shadowy radical Islamic group known as al-Qaeda, killed some 3,000 people during the bloodiest terrorist assault in US history. American Airlines Flight 77, which had just taken off from Dulles International Airport in Northern Virginia on a flight to Los Angeles, was seized by al-Qaeda terrorists and crashed through the Pentagon’s western wall at 9:37 a.m. North Dakota’s 119th Fighter Wing was stationed at the North American Aerospace Defense Command site on Langley Air Force Base, Virginia. Shortly after the attack, the 119th’s F-16 fighters established a combat air patrol over the nation’s capital. In addition to all the passengers aboard Flight 77, 125 people inside the Pentagon were killed and over 600 others were injured seriously enough that they had to be transported to local hospitals.

The North Dakotan air guardsmen were joined that day by F-16s from the District of Columbia’s 113th Wing, based at Andrews Air Force Base, Maryland, and Virginia’s 192nd Fighter Wing from Richmond, as well as active duty Air Force and Navy fighters. Those fighter pilots were under orders to use deadly force if necessary to protect the nation’s capital from further attacks. Within 24 hours of the terrorist attacks, 34 ANG fighter units across the country had launched aircraft. Fifteen of the units flew 179 combat air patrols, presidential escorts, and Federal Emergency Management Agency (FEMA) support missions. In addition, ANG tanker, airlift, and rescue units flew scores of sorties that day. Hundreds more Air Guard personnel from various support fields including chaplain services, civil engineering, combat communications, medical, and security forces were either activated or notified to stand-by for emergency duty. The majority of air guardsmen involved in responding to the 9/11 national emergency were traditional members of their units who volunteered to help defend their country on that terrible day.

Continuous combat air patrols were maintained over Washington, DC, and New York City until the spring of 2002. The bulk of those missions, conducted under the auspices of Operation Noble Eagle, were flown by Air Guard pilots. Ironically, one result of the terrorist attacks was the saving of the continental air defense mission. It had been viewed as a fading post-Cold War “sunset mission” by some senior military officers and high-level government officials, but the attacks of 9/11 inspired a major effort to build a coherent homeland defense system for the continental United States against terrorism and other threats.