This is now Obama's war. The failure will be his, the cost ours. The tragedy will be Afghanistan's.

We are bogged down in Afghanistan in a war that is not only unwinnable, but even undefinable. The longer a war goes on, the more difficult it is to end, but Obama has already foreclosed the one option that the situation demands, which is withdrawal.

Barack Obama, apparently suffering a brain cramp, has rebranded Afghanistan as a "war of necessity." That very term, war of necessity, is intended to distinguish such wars from so-called 'wars of choice,' or in plainer English, wars of aggression.

A war of choice (sometimes called an elective war) is one you can take or leave without injury to the national interest; a war of necessity is one where such interests are risked by not using force to impose one's will.

Note that responding to an actual attack or the credible imminence of one -- the justification for war in international law -- is unnecessary as a condition for wars of necessity. One need only satisfy oneself that one's "interests," as defined by oneself, are sufficiently inconvenienced to be set to rights by force.

That is how we found ourselves involved in Korea and Vietnam, two countries that never attacked us and never could, not to mention exotic places like Lebanon and Grenada. That is the way empires act. Like all bullies, empires sometimes get their noses bloodied (while the rest of the world silently cheers). That is what happened to us in Korea and Vietnam, and in Iraq.

But weren't we attacked by or at least from Afghanistan, and isn't that war, at least, justified?

Actually, no. To say we were attacked by Afghanistan is absurd; so, too, is to say we were attacked from it. Sept. 11 was tactically launched from Germany, and some of the hijackers were trained in American flight schools. Should we have attacked the Germans, or ourselves?

True, the Taliban were hosts to Al Qaeda and knowingly permitted training camps on territory at least nominally under their jurisdiction. They were thereby arguably complicit in the Sept. 11 attacks, even if, as they claimed, they were quite unaware of them. So, of course, were the Saudis, whose participation was far more efficacious. The best that can be said is that we chose a symbolic target in a war that technically met the requirements of legitimate military action, but without offering a real site of reprisal or a meaningful battlefield. In short, we were attacked not by another state, but by terrorists based, literally, in dozens of states.

Undefinable

It is important to recognize this in order to understand why we are bogged down in Afghanistan in a war that is not only unwinnable, but even undefinable. "Al Qaeda in Afghanistan," if there ever was such an entity, it has long since melted away into the friendly confines of Pakistan's western provinces; no more than a hundred of its operatives remain in Afghanistan itself according to the President's own national security advisor, Jim Jones.

It hardly takes the armies of 42 nations to deal with that. Meanwhile, we have created a tenacious new foe in the Taliban, who, according to American intelligence, actually control more territory as a guerrilla force than they did as a putative government. In other words, the more we attack them, the more powerful they grow.

This is not difficult to understand. The Taliban are tribally based; we are foreign invaders in a land that has always rejected them. We have caused much social disruption and inflicted many deaths. We have nothing to offer the Afghan population but more of the same.

The puppet regime we set up is a narco-state that has sown corruption from top to bottom of Afghan society; no army or security force we train will ever be more than an adjunct to a criminal enterprise, unless it becomes an independent proprietor itself. We can do nothing but harm, and we accomplish nothing but to spread destabilization to Pakistan, a state whose fate does concern us.

The longer a war goes on, the more difficult it is to end. President Eisenhower was able to end the Korean War and De Gaulle the Algerian one because they had the military prestige to do so without suffering unacceptable political damage. Barack Obama does not have this advantage. However, we elect leaders to make hard choices, and he sought the responsibility. The war in Afghanistan is now his. He has already foreclosed the one option that the situation demands, which is withdrawal. The failure will be his, and the cost ours. The tragedy will be Afghanistan's.