"Accepting Peace Prize, Obama Evokes 'Just War,'" notes the headline in the New York Times, referring to President Obama's speech accepting the Nobel Peace Prize. President Obama did indeed invoke the concept of a "just war." But tellingly, he did not try to argue that the U.S. war in Afghanistan meets the criteria to be judged as a "just war."

A plausible explanation for the President's failure to argue that the war in Afghanistan is a "just war" is that he recognizes that such an argument would not be convincing.

As President Obama noted in his speech, there are criteria involved in the "just war" concept. It isn't just a matter of proclaiming that a war is justified. There are tests.

This matters, because a substantial part of the U.S. and world population subscribes to the theory of "just war." In particular, more than a fifth of the U.S. population are estimated to identify as Catholics. The concept of "just war" - that wars can be considered "just" only if they meet certain criteria - is an official doctrine of the Catholic Church.

Here's part of what the official Catechism of the Catholic Church has to say about this:

Avoiding war

2307 The fifth commandment forbids the intentional destruction of human life. Because of the evils and injustices that accompany all war, the Church insistently urges everyone to prayer and to action so that the divine Goodness may free us from the ancient bondage of war.

2308 All citizens and all governments are obliged to work for the avoidance of war.
However, "as long as the danger of war persists and there is no international authority with the necessary competence and power, governments cannot be denied the right of lawful self-defense, once all peace efforts have failed."

2309 The strict conditions for legitimate defense by military force require rigorous consideration. the gravity of such a decision makes it subject to rigorous conditions of moral legitimacy. At one and the same time:

- the damage inflicted by the aggressor on the nation or community of nations must be lasting, grave, and certain;
- all other means of putting an end to it must have been shown to be impractical or ineffective;
- there must be serious prospects of success;
- the use of arms must not produce evils and disorders graver than the evil to be eliminated. the power of modern means of destruction weighs very heavily in evaluating this condition.

These are the traditional elements enumerated in what is called the "just war" doctrine.
The evaluation of these conditions for moral legitimacy belongs to the prudential judgment of those who have responsibility for the common good.

The U.S. war in Afghanistan does not meet these criteria, and that's why it's not surprising that President Obama didn't try to argue that it does.

According to the current statements of U.S. officials, the target of the war and the current proposed escalation is not Al Qaeda - estimated to have 100 or so fighters in Afghanistan - but the Afghan Taliban insurgency, which, it is alleged, would shelter Al Qaeda if it returned to power. "Success" is now defined by the Administration fuzzily as "degrading" the Taliban.

- the "damage" inflicted by the difference between the power of the Afghan Taliban today and the power the Afghan Taliban will have if it is "degraded" by the U.S. "surge" is not "lasting, grave, and certain." Even top officials of the U.S. government, according to press reports of the Administration's review, do not believe that it is inevitable that the Afghan Taliban would provide a "safe haven" to Al Qaeda in Afghanistan, even if the Afghan Taliban were to take control of the entire country, an unlikely prospect (even prior to the U.S. invasion in 2001, the Afghan Taliban did not control the entire country.) And, as counter-terrorism expert Paul Pillar has noted, even if Al Qaeda did re-establish a "safe haven" in Afghanistan, it would not significantly increase the terrorist threat to the United States, because such "safe havens" aren't that important to planning terrorist attacks, and because Al Qaeda has ample recourse to such "safe havens" elsewhere.

- all other means of putting an end to the "damage" - such as political negotiations in Afghanistan and the region - have not been shown to be impractical or ineffective;

- "serious prospects of success": now that the criterion for success has been defined as only "degrading" the Taliban, perhaps there is a serious prospect of success - that's the beauty of fuzzy goals - it's hard to say that they can't be achieved. But it is critical to keep in mind that it is this current much more modest official goal of "degrading" the Taliban - not more ambitious but unachievable goals such as "eliminating" Al Qaeda or the Taliban - which has to be measured against the moral costs of the war. Since the United States Government now officially concedes that the Taliban will be part of Afghanistan's future no matter what the United States does, arguing that it is a bad thing for the Afghan Taliban to continue to exist cannot be part of a rational argument for continuing the war.

- the use of arms already has produced evils and disorders graver than the evil to be eliminated, and will almost certainly continue to do so. The difference to the world and to Afghanistan between whether the Afghan Taliban have their present power or the power they will have after being "degraded" cannot possibly justify the destruction of American and Afghan lives that is the guaranteed consequence of continuing and escalating the war.