WASHINGTON — This is not crime. This is war. One of the reasons there are terrorists out there capable and audacious enough to carry out the deadliest attack on the United States in its history is that, while they have declared war on us, we have in the past responded (with the exception of a few useless cruise missile attacks on empty tents in the desert) by issuing subpoenas.

Secretary of State Colin Powell's first reaction to the day of infamy was to pledge to "bring those responsible to justice." This is exactly wrong. Franklin Roosevelt did not respond to Pearl Harbor by pledging to bring the commander of Japanese naval aviation to justice. He pledged to bring Japan to its knees.

You bring criminals to justice; you rain destruction on combatants. This is a fundamental distinction that can no longer be avoided. The bombings of Sept. 11, 2001, must mark a turning point. War was long ago declared on us. Until we declare war in return, we will have thousands of more innocent victims.

We no longer have to search for a name for the post-Cold War era. It will henceforth be known as the age of terrorism. Organized terror has shown what it can do: execute the single greatest massacre in American history, shut down the greatest power on the globe, and send its leaders into underground shelters. All this, without even resorting to chemical, biological or nuclear weapons of mass destruction.

This is a formidable enemy. To dismiss it as a bunch of cowards perpetrating senseless acts of violence is complacent nonsense. People willing to kill thousands of innocents while they kill themselves are not cowards. They are deadly, vicious warriors and need to be treated as such. Nor are their acts of violence senseless. They have a very specific aim. To avenge alleged historical wrongs and to bring the great American satan to its knees.

Nor is the enemy faceless or mysterious. We do not know for sure who gave the final order but we know what movement it comes from. The enemy has identified itself in public and openly. Our delicate sensibilities have prevented us from pronouncing its name.

Its name is radical Islam. Not Islam as practiced peacefully by millions of the faithful around the world. But a specific fringe political movement, dedicated to imposing its fanatical ideology on its own societies and destroying the society of its enemies, the greatest of which is the United States.

Israel, too, is an affront to radical Islam, and thus of course must be eradicated. But it is the smallest of fish. The heart of the beast — with its military in Saudi Arabia, Kuwait, Turkey and Persian Gulf; with a culture that "corrupts" Islamic youth; with an economy and technology that dominates the world — is the United States. That is why we were struck so savagely.

How do we know? Who else trains cadres of fanatical suicide murderers who go to their deaths joyfully? And the average terrorist does not coordinate four hijackings within one hour. Nor fly a plane into the tiny silhouette of a single building. For that you need skilled pilots seeking martyrdom. That is not a large pool to draw from.

These are the shock troops of the enemy. And the enemy has many branches. Hezbollah in Lebanon, Hamas and Islamic Jihad in Israel, the Osama bin Laden organization headquartered in Afghanistan, and various Arab "liberation fronts" based in Damascus. And then there are the governments: Iran, Iraq, Syria and Libya among them. Which one was responsible? We will find out soon enough.

But when we do, there should be no talk of bringing these people to "swift justice," as Karen Hughes dismayingly promised mid-afternoon Tuesday. An open act of war demands a military response, not a judicial one.

Military response against whom? It is absurd to make war on the individuals who send these people. The terrorists cannot exist in a vacuum. They need a territorial base of sovereign protection. For 30 years we have avoided this truth. If bin Laden was behind this, then Afghanistan is our enemy. Any country that harbors and protects him is our enemy. We must carry their war to them.

We should seriously consider a congressional declaration of war. That convention seems quaint, unused since World War II. But there are two virtues to declaring war: It announces our seriousness both to our people and to the enemy, and it gives us certain rights as belligerents (of blockade, for example).

The "long peace" is over. We sought this war no more than we sought war with Nazi Germany and Imperial Japan or cold war with the Soviet Union. But when war was pressed upon the greatest generation, it rose to the challenge. The question is: Will we?

Charles Krauthammer's column usually appears Monday on editorial pages of The Times. The Washington Post Writers Group can be contacted via e-mail at writersgrp@washpost.com.