A central political issue that Americans must now squarely face in the aftermath of the war on Iraq is: Should the U.S. government have the power to wage war to free foreigners from tyranny in their own land? The correlative moral issue is: Is it morally right to sacrifice one group of people in order that another group of people may be freed from tyranny?

Consider an example: Suppose that terrorist Timothy McVeigh, instead of setting off his bomb in the Oklahoma City federal building, had taken everyone in the building hostage, threatening to set off a bomb that would kill, say, 1,000 people inside. Suppose McVeigh had said, “If the president will order the killing of 50 federal agents who took part in the Waco massacre, I will not set off the bomb and will release the 1,000 people in this building.”

Would anyone honestly argue that the moral course of action would be for the government to kill 50 innocent people in order to free the other group of 1,000 innocent people?

Is it any different with respect to ousting a brutal foreign dictator from office with the aim of freeing his citizens from his tyrannical rule? After all, as we have found in Iraq, it’s not simply a question of just removing the dictator from office. War is a process that by necessity requires the killing of multitudes of innocent people, both civilians, albeit accidentally, and ordinary enemy soldiers.

Thus, the moral issue with which every American must struggle in the aftermath of the war on Iraq is: Were the killings of thousands of Iraqi people, both military and civilian and in the process of freeing the Iraqi people from tyranny, morally justified?

That is the issue, I believe, that the Pope was raising on the eve of war, when he suggested that those who wage the war will ultimately have to answer to God. He was implying, I believe, that the killings of the Iraqi people that would necessarily occur in the course of the war would violate the Sixth Commandment.

But how can this be? Doesn’t God let people off the hook when it comes to war?

That’s what the “just-war” concept is all about. Not every war is just, and when it is not just, the killings that occur within the context of the war violate fundamental moral principles regarding the wrongful taking of life as well as God’s “Thou shalt not kill” commandment. Conversely, if the war is just, the killings are justifiable, both morally and in the eyes of God.

Consider the plight of Saad and Sindous Abbas, 34 and 30 years old, who lost three daughters in the war. What moral right do we have to say to them, “The loss of your daughters was worth it because you and other Iraqis are now free”?

Or consider 12-year-old Ali Ismaeel Abbas, who lost not only his family but also both of his arms as a result of a missile that hit his home. He cried out that if he couldn’t get his arms back, he’d rather die. What moral right do we have to say to him, “Losing your family and your arms was worth it because you and other Iraqis are now free”?

When U.S. Ambassador to the United Nations Madeleine Albright was asked about the horrific effects of the economic sanctions that the U.S. government had enforced against Iraq since 1991, including the deaths of an estimated half-a-million Iraqi children, she responded, “I think this is a very hard choice, but the price — we think the price is worth it.”

But worth it to whom? It’s a moral question that Americans now need to ask themselves.

Mr. Hornberger is founder and president of The Future of Freedom Foundation.