The second component includes two broad principles: Of discrimination and proportionality. The first distinguishes legitimate targets of war (combatants) from all others (non-combatants), while the second attempts to prevent undue or excessive force by requiring a reasonably proportionate measure of force--and no more--toward a specific target.

The purpose of the Just War tradition is to make the decision to go to war as difficult as possible and to clearly relegate war to a course of last resort. Every alternative option of resolving a conflict by a means other than warfare must be employed and exhausted.

The Just War theory has a long and established history, with proponents who believe it is still useful and necessary, and critics who believe it is obsolete and deserving of abandonment.

The complexities of war, the consequences of the "fog" of war, the increased lethality of 21st century armaments, the evolving concepts of conventional vs. chemical, biological, radiological, nuclear vs. asymmetrical warfare all make the concept of war a wholly different reality from that of the 4th-century ethicists who fleshed out many of the enduring principles of today's just war tradition.

Without some credible and recognized convention that morally challenges the urge to resort to war and demands a public forum for accountability, the risk is a loss of any public discourse at all, or at least an established moral basis for doing so. The significant investment of the lives and treasure of a nation, and the current and future course of a nation's well-being, provide all the justification needed for maintaining that discourse with a standard of integrity that does not betray the cause of justice.

Not to do so is an abdication of the responsibility of a free citizenry.

The Rev. Robert Bruno is a Roman Catholic priest and has been a military chaplain since 1980. He is currently serving as Joint Staff Chaplain, Religious Affairs Office, Office of the Chairman of the Joint Chiefs of Staff.