In an ill-defined war, what next?

With the military side of the war in Afghanistan going reasonably well, it is time to consider the question: "What next?"

In what the president calls the Bush Doctrine, he has said the objective of the war is to end terrorism, but he has never defined terrorism with much specificity. In a pep talk to the 101st Airborne Division in Fort Campbell, Ky., a couple of weeks ago, the president used this definition: "If you harbor terrorists, you are terrorists. If you train or arm a terrorist, you are a terrorist. If you feed a terrorist or fund a terrorist, you're a terrorist...."

This brings back memories of the cold-war definition by analogy of a communist: "If it walks like a duck and quacks like a duck, it's a duck." This begged the question of what is a communist just as President Bush begs the question of what is a terrorist.

The president included supporters of terrorism among those incurring the wrath of the United States. Fair enough. Common sense tells us that supporting includes providing financing and a safe haven. In the Bush definition, does it also include, as has been suggested, possession or work on development of weapons of mass destruction - nuclear, chemical, or biological weapons?

Beginning in the depths of the cold war, prevention of the proliferation of these weapons was long an objective of US foreign policy. In this we have largely failed, especially with respect to nuclear weapons. Are we now going to pursue the nonproliferation goal through military instead of diplomatic channels?

The 19th-century German military thinker Karl von Clausewitz said that war is the continuation of politics by other means but do we want to push it this far? Are we going to make even the possession of chemical, biological, and nuclear weapons a casus belli? If so, where do we draw the line between countries such as India, Pakistan, and Taiwan on the one hand and Iraq, Iran, Libya, and North Korea on the other?

A case can be made for following up Afghanistan in Iraq. The war to eject Iraq from Kuwait was ended prematurely with an Iraqi agreement, since broken, to give United Nations inspectors free rein to search for weapons of mass destruction. With the American public in a warmaking mood and US military forces in the area, it can be argued that now is a good time to finish the job. But what about other countries with such weapons?

Is our war against terrorism aimed only at protecting the US homeland? Or does it include US interests abroad? Or anybody anywhere? The president has sometimes hinted at this last definition, which would make the US the world policeman and the protector everywhere of those unable to protect themselves - a daunting assignment far beyond our capabilities. He has also sometimes limited his doctrine to terrorist organizations, such as Al Qaeda, with a global reach, or ambitions for a global reach. This is a considerably more modest goal.

Finally, how do we know when we have won? This is a war unlike any other. It has as starkly clear a beginning as Pearl Harbor gave to US entry into World War II. Although we are confident we know who started the war on terrorism, they are not as clear targets as the Japanese, nor are they likely to sign a surrender document. More likely, they will recede into the mists from which they came. Will we know this with certainty when or if it happens, or are we doomed to live indefinitely with the fear of another attack on the scale of Sept. 11 hanging over us?

And what collateral responsibilities are we assuming? The United Nations is struggling to put together a new Afghan government, an effort in which the US must necessarily play a key role. So we find ourselves once again in nation-building, a task of endless complexity, and one in which we do not have a good track record.

Since the collapse of the Soviet Union ended the cold war 12 years ago, the United States has been searching for an overall foreign policy to replace the anti-communism of that era. We may have found it in antiterrorism, but we have not found a successor to the cold war's containment policy for dealing with the Soviet Union.

Pat M. Holt is former chief of staff of the Senate Foreign Relations Committee.