As President Bush tries to determine an appropriate response to the “acts of war” perpetrated on the United States, religion will play an important role in building consensus.

The morality of waging war is a moral issue with which Christians have long struggled.

Throughout the Church's 2,000-year history, different strains have emerged — usually reflecting historical context. The early Church was basically pacifist. The Gospels’ counsel to turn the other cheek was foremost in framing this attitude (Luke 6:29). Being on the fringe of society and under-represented in the military and government, Christian opinion mattered little.

The advent of the great Church under Constantine, however, required Christian accommodation due to the Church's presence in the political life of the Empire. St. Augustine, therefore, began to develop moral codes for the rules of war which have come to be known as the “Just War” theory. Since the fifth century, these principles have served as a guide for Christian nations for the declaring of war and the legitimate means of prosecuting it. This traditional teaching of the Church has much to offer. Yet, in the present crisis, certain particulars for its valid application deserve special attention and thought.

There are four basic criteria that must be met for a war to be “just”:

1. It must be in response to the lasting, grave and certain damage caused by an aggressor;

2. all other means of resolution must be shown to be impractical and ineffective;

3. there must be a serious prospect for success of the planned offensive actions; and

4. the response must be proportional, in other words, not causing greater evil than the one trying to be eliminated.

It seems quite certain that the first principle of self-defense justifies the United States to take military action. This is also clearly recognized in the United Nations Charter, Article 51.

However, the next three criteria become problematic. Part two requires that all other means of curtailing enemy activity must be exhausted. This usually means diplomatic negotiations. When the enemy is a recognized state, channels such as the United Nations or international courts are legally recognized tools to solve the conflict or bring war criminals to justice.

The recent U.N. peacekeeping actions in Bosnia and the convening of the International Criminal Tribunal for the former Yugoslavia at The Hague in prosecuting Slobodan Milosovic stand out as a current examples. In the situation at hand, however, there is a serious question as to with whom we would negotiate. The terrorists do not represent a legitimate state, and war traditionally is not declared on an individual. The only avenue that seems open is to negotiate with those countries harboring these terrorist organizations to bring those responsible to justice.

This presumes that the states involved are sensitive to international law. If these efforts fail, may we invade a sovereign nation to extricate the criminals? This point is dubious in international law. The kidnapping of Adolf Eichmann and the Israeli rescue of the hostages held in Entebbe, Uganda, are still debated.

Part three calls for a reasonable assurance that our efforts to subdue the enemy will be successful. This was much more viable when wars were geographical and when the enemies’ identity and resources were clearly delineated. These were obvious during, for example, World War II, but the guerilla warfare of Vietnam provided the first glimpse of the difficulty in prosecuting a less clearly defined enemy.

Part four calls for a proportional response. If, as it seems, Osama bin Laden is behind the hijackings, a proportional response will be difficult to achieve because his organization — we are told — has cells in numerous cities throughout the world. How do we successfully exterminate them without extending the evil to innocent people living in cities throughout the world and even the innocent people living in Afghanistan where he is in hiding?

These questions must be wrestled with as America plans its response to the evil inflicted this past Tuesday. While defense and even retribution are a valid Christian response to atone for the evil inflicted on a society, how we achieve it will require the best thinking and highest ideals that those of good will are capable of.

The Christian response will require, even more so, a tremendous amount of prayer for wisdom so that our actions reflect God's will for peace and justice in an imperfect world.

Father Michael Orsi is chaplain of, and a research fellow at, Ave Maria Law School in Ann Arbor, Michigan.