In the 2002 State of the Union address and at the West Point graduation ceremony, President Bush articulated a new strategy for the United States in dealing with the threat of terrorism with weapons of mass destruction: preventive war. The president argued pessimistically that "time is not on our side" and that we could not afford to "wait on events, while dangers gather." Americans must be ready for "pre-emptive action" to defend our lives.

The argument is straightforward. In the Cold War, the United States relied upon the threat of nuclear annihilation to deter other states from attacking us or challenging our interests. This strategy of deterrence worked because our main adversary, the Soviet Union, was led by reasonable men who valued their lives and positions and hence had a lot to lose in a nuclear war. Today, however, we face terrorist networks such as Al Qaida that are suicidal and irrational. They have nothing to lose and so are undeterrable. Therefore we need to strike first, to attack these networks and any state that we suspect is sympathetic to them, especially if they have weapons of mass destruction or are close to acquiring them. Time is not on our side because the longer we wait, the greater the destructive capabilities of our enemies and the more likely they are to pass them on to undeterrable terrorist groups.

This is the logic of preventive war, to attack now because our enemies are growing stronger and will attack us later with disastrous consequences. It is better to fight now rather than later, because now our costs will be lower and our chance of prevailing higher. This logic has often motivated decisions to start a war. The ancient Greek historian Thucydides tells us that Sparta attacked Athens because Spartans feared its growing power. The result was a 26 year war that was extremely costly for both sides, and though Sparta did eventually prevail the war so weakened the Greek city states as to invite foreign intervention in their affairs.

More recently, in a case well worth reflecting on, Germany at the beginning of the twentieth century believed it faced a rising threat from Russia. In 1905 Russia was defeated by Japan in the far East, and weakened by revolutionary disturbances at home. With her Russian ally prostrate, France alone was no match for Germany and a dispute over Morocco arose which could have served as a pretext for war. Some Germans advocated attacking at that moment of maximum advantage, but the British stood by the French and the German leadership feared the people would not support them in a war over colonial interests. So Germany waited, and as the years went by, her military and political leaders grew more pessimistic. Russia began to recover from defeat and near-revolution, and her economy began to grow again. Because of Russia's vast population and undeveloped resources, it was clear that if Russia were allowed to grow undisturbed, it would eventually become vastly powerful, perhaps more powerful than Germany. In 1913, in response to German and French military increases, Russia also announced a program to increase the strength of her armed forces and improve her strategic rail system so that she could more quickly bring forces to bear against Germany.

Fearful of the projected increase in Russian power, and convinced that time was not on her side, Germany initiated the First World War in August 1914. The primary goal was to destroy Russia before she grew so strong as to be unconquerable. In this sense, Germany's goal, narrowly speaking, was security, she was acting out of fear and to protect herself, just as the Bush administration wishes to protect America by acting preemptively against Iraq. Unfortunately for Germany, and her neighbors, this quest for security was a catastrophe for all of Europe which was not really healed until the fall of the Berlin Wall in 1989. For Germany, though more than a match for her two immediate enemies--the Franco-Russian alliance--was fought to a bloody standstill on the Western front, and though temporarily successful in the east in 1917, lost the war in 1918. The millions of fatalities and deep hatreds engendered by the war led eventually to the rise of Hitler and the Second World War, while the collapse of the Russian autocracy led to the Bolshevik revolution and the eventual Cold War standoff. Thus for Germany, the war produced not security but heavy casualties, defeat, extremism, renewed warfare and devastation, forty five years of partition and permanent territorial losses.

Why did this strategy of preventive war failed to produce the desired results? One key answer is that initiating a war sends the worst possible signal to other states about one's motivations, and hence tends to generate overwhelming counter-coalitions that defeat the initiator. States face constant uncertainty about each other's motivations. Some states just want security, to live in peace with what they have. Others are more aggressively motivated, they want new lands or world domination. Asking a leader about his ultimate intentions is likely to be futile because even a Hitler will claim to have modest ambitions in order to lull potential victims into a false sense of security. Therefore, states look to each other's actions, more than their words, in assessing each other's motivations. States which flout international law, ignore the desires of others, extend their power as far as it will reach, dominate weaker neighbors, etc, signal to others that they have aggressive motivations and cannot be trusted. Such states tend to become encircled with a ring of enemies, as the Soviet Union was during the Cold War.

Launching a preventive war is the surest way to generate this kind of self-encirclement. Germany's attack in 1914 persuaded the fence-sitting British that Germany was aggressive and had to be stopped, and British troops helped halt the initial German offensive and held the line for four years. Even distant America was ultimately persuaded that Germany was a threat and entered the war against her in 1917, just in time to stop the 1918 German offensive that otherwise would have won the war for Germany.

The same pattern has been repeated many times. The Japanese pre-emptive strike on Pearl Harbor convinced the Americans that the Japanese militarists had to be destroyed, and hence generated the very determination to fight a long war that Japanese planners hoped would not exist. German and Japanese protests that they were only acting to increase their security fell on deaf ears because actions speak louder than words. Preventive attacks persuade the opponent and third parties that one is an aggressive state, even if they are not motivated by aggression.

In light of this historical pattern, the United States should think long and hard before it adopts a policy of waging preventive war. Our traditional strategy has been to wait for enemies to unambiguously identify themselves, by attacking others or ourselves, and then to respond with overwhelming force and with the aid and blessing of a large coalition of similarly minded states. These coalitions were a product of the aggressive conduct of the enemy, other states saw the same signals we did and shared our beliefs about what needed to be done. If we instead become the initiator, it is the United States that will look aggressive in the eyes of the world, and it is our enemies that will begin to collect allies against us.

In the current conflict with Iraq, we have signally failed to regenerate the coalition that supported us in the Gulf War, and even many of our NATO allies are beginning to distance themselves from us. Terrorist groups such as Al Qaida may be undeterrable. Regime change in Iraq is highly desirable from many points of view. But we should not jump to the conclusion that a Saddam with nuclear weapons would be undeterrable, or that he could not be dissuaded from passing weapons of mass destruction to terrorists by the threat that if we are hit with such weapons, he will be first on the list for retaliation. Iraq had chemical and biological weapons and warheads capable of delivering them during the Gulf War, but refrained from using them presumably because of the threat that U.S. forces would proceed to Baghdad if it did. Before we launch a preventive war, we should carefully consider the alternatives, lest we join Kaiser Wilhelm in the long list of those who sought security through preventive war, but did not find it.