My 8-year-old son saw the news reports about Osama bin Laden’s death buzzing Monday on our TV.

He took particular note of scenes of cheering crowds: flag-wavers in Times Square and at Ground Zero in New York City, baseball fans in Philadelphia, patriots in Boston, enthusiastic students on college campuses. All were clapping, smiling and chanting in response to the news that U.S. Navy SEALs had cornered and killed the world’s most wanted terrorist.

My son wondered about the cheering, concluding that it was OK because “this man killed thousands of others.” His questions gave us an opportunity to talk about war, terrorism and, most importantly, justice.

Perhaps many Christians shared my son’s initial uncertainty since hearing of bin Laden’s demise. Surely it’s a good thing that he no longer is able to lead murderous schemes. But what exactly are we cheering about?

Hadn’t my 8-year-old heard me talking little more than a week before, on Good Friday, about forgiveness?

Perhaps he was trying to connect the dots between the cheering on TV about a man’s death and his Sunday school teacher’s words about turning the other cheek. His mother and I have tried, on occasion, to teach our son to pray for his enemies (which, in second grade, usually means the boy who broke your Legos).

And yet the success of American forces in finally ending this particular man’s reign of terror is an act of justice that even a child can recognize.

Western civilization is heir to a rich “just war” tradition of wrestling with the morality of war. This tradition can help us navigate these kinds of sentiments.

The idea of a just war recognizes the legitimacy of using military force to respond to injustice when ordinary political means aren’t available or effective. The Christian doctrine of just war brings moral principles to bear on decisions about when and how to wage armed conflict.

For example, military action must be waged by a proper authority. It must have a reasonable probability of success. And it must distinguish between combatants and civilians.

A just war also is one undertaken with the right intention—not hatred or revenge, but justice.

These and other principles of just war arose out of Christian convictions about the value of human life, social order and the rule of law. They track with the biblical responsibility for governments to punish wrongdoers and administer justice. Scholars of the doctrine point out that, when appropriately used, armed combat aims to bring about a peaceful and just social order for both sides of the conflict.

Bin Laden long undermined these goals and standards of justice. He recklessly ignored the value of human life. He organized terrorist attacks on American citizens and institutions, among many others. He called for jihad in the name of revenge and religious hatred. He targeted innocent civilians.

Ideally, established political means would enable the U.S. government to respond to these injustices. But in the absence of such means, the tradition of just war views armed conflict as an appropriate way to resist evil, protect innocent lives and restore just social relationships.

I didn’t go into detail about all these principles with my 8-year-old son. Nor did I have enough knowledge of the raid in Pakistan to apply them point by point. But knowing the tradition enabled me to help my son sort out his reactions to bin Laden’s death.

I was able to remind him that acting out of vengeance or hatred is wrong, but that we are called to seek justice. The cheering in our home is not gloating over someone’s death. Rather, it is celebrating the fact that a terrorist’s murderous acts have been judged wrong, and he won’t be committing them again.

Justice has been done. May it continue to guide the actions of America’s citizens and government both at home and abroad in the face of evil and injustice.

Ryan Messmore is the William E. Simon Fellow in Religion and a Free Society at The Heritage Foundation.