Since 9/11, James Carroll has used his column in the Boston Globe to examine America's response to the attacks. A former Paulist priest and a fierce opponent of the Vietnam War as a youth, Carroll's writings are unsparingly critical of the wars in Afghanistan and Iraq. Though decidedly liberal, Carroll uses history and theology to explore the moral and spiritual underpinnings of our foreign policy. The result has been some of the most honest, interesting, and alarming writing on the war on terror available. His post 9/11 columns have been collected in a new book, "Crusade." We talked with him recently about the past three years and what's to come.

In "Crusade," you quote Thomas Mann saying the First World War forced him to "rethink his fundamental assumptions." What are the fundamental assumptions of this war?
American virtue--the assumption that our motives are beyond reproach. The United States doesn't regard itself as capable of evil acts. Therefore, we don't feel obliged to be self-critical or self-reflective, and we don't observe the safeguards that are necessary for human behavior if abuses are going to be avoided, like the treatment of prisoners in Abu Ghraib.

You say that moral certainty is not good theology.
In the Christian tradition, the fact that the Messiah is coming again is really shorthand for saying that the kingdom is incomplete, unfinished, radically uncertain. There's an inevitable modesty that comes that. It doesn't matter, really, whether you're a Jew who's expecting the Messiah for the first time, or a Christian expecting the Messiah for the second time. These are not empty, pious categories, these are profoundly significant theological affirmations. And they all point in the same direction, which is toward the need for self-criticism, the permanent need for repentance.

One of the president's mistakes, you say, was characterizing the war on terrorism as a crusade. You write that the original crusades changed the theology of the Christian church at the time.
The seven or eight crusades launched after 1096 were mostly wars against Islam. They institutionalized violence as a sacred act--that one way to fulfill the will of God is by killing in God's name. Crusaders were promised "plenary indulgence" if they died in the act of battle, that is, they were promised immediate access to heaven. We condescend toward Islamic believers who describe the reward for death in jihad as immediate access to heaven. Well, that idea took hold in Christianity too, in the crusades.

The theological underpinning of this notion, which we see in the theology of St. Anselm, who asked, 'Why did God become a man?' His answer was that God became a man precisely to die a violent death on the cross. It's not an accident that St. Anselm's "Cur Deus Homo" appears within two years of the launching of the first crusade.

The Second Vatican Council de-emphasized the cross, and moved away from understanding the Mass as a sacrifice. It reclaimed the tradition that the Mass is a banquet, a celebration. Good Friday is not the liturgical high point of the year anymore-it was when I was a child.

Has the pope said anything that showed he is aware of these currents or worried about them?
On the one hand, John Paul II is profoundly skeptical of war. He opposed the Gulf War in 1991. He opposed the NATO air war against Serbia over Kosovo and he opposed the Iraq War. I regard that as part of the Second Vatican Council's vision. John XXIII's encyclical Pacem en Terris is a real repudiation of the war-friendly theology of Pius XII, who firmly allied himself with the consensus that it's better to be dead than red. John XXIII moves the church away from that, toward life. It's a recovery of a profoundly Biblical, one could say Jewish, affirmation "l'chaim." The meaning of Jesus is not in death, it's in life.

There are other ways in which I think the pope is profoundly rooted in a medieval Christology, and is quite at home with the theological significance of suffering. He carries his own suffering as a kind of sacrament, which I don't presume to criticize, but I do think there is a kind of pious misappropriation of suffering that is an old problem in Latin Christianity and we should leave it behind.

Many came to oppose with the Iraq war when they found out there were no weapons of mass destruction. You opposed it even when you thought there might be.
My opposition didn't depend on there not being weapons of mass destruction because I believed what the inspectors were saying up to the start of the American bombing campaign. [Chief U.N. arms inspector] Hans Blix and Scott Ritter, a former inspector, were emphatically saying that the inspections regime showed ample promise of containing Hussein. War is an extreme act, our allies were saying, and the present situation in no way justifies it.

Are you surprised at the public's response to the war? As someone who spoke out against Vietnam, do you wonder where the outrage is?
I would take it back to 9/11. I think Americans spent three or four decades, since Vietnam certainly, feeling profoundly guilty about our role in the world. Not just the wars, but the cost of our affluence to impoverished people. There are a billion people in the world who are relatively well off, but there are five billion who are desperately poor.
Americans are decent people and I think we feel the burdens of these inequities quite deeply.