All talk about "victory" and "defeat" in our current wars may actually be beside the point. Whatever happens in Iraq and Afghanistan, the vulnerability of American cities to both mass-destruction terrorism and ballistic missile attack will remain more or less unchanged.
Consider how different matters were in the past.
At Thermopylae, we learn from Herodotus, the Greeks suffered a terrible defeat in 480 BC. But then, Persian King Xerxes could not even contemplate the destruction of Athens until he had first secured a decisive victory.
Only after the Persian defeat of Leonidas and his heroic defending forces would the Athenians be forced to abandon Attica. Transporting themselves to the island of Salamis, the Greeks would witness the Persians burning their houses and destroying their sacred temples on the Acropolis.
Why should this ancient Greek tragedy be significant for us? Until the onset of our Atomic Age, states, city-states, and empires were essentially secure from homeland destruction unless their armies had already been defeated.
For would-be aggressors before 1945, a capacity to destroy had always required a prior capacity to win. Without a victory, intended aggressions were never really more than military intentions.
This is no longer the case. From the standpoint of ensuring any one state's national survival, the goal of preventing a classical military defeat has become secondary. The strategic implications of this transforming development are utterly far-reaching.
Lessons from Thermopylae
After suppressing revolts in Egypt and Babylonia, Xerxes was finally able to prepare for the conquest of Greece. In 480 BC, the Greeks decided to make their final defense at Thermopylae. This particular site was chosen because it offered what military commanders would call "good ground."
Here was a narrow pass between cliffs and the sea – a place where relatively small numbers of resolute troops could hold back a very large army. For a time, Leonidas, the Spartan king, was able to defend the pass with only about 7,000 men (including some 300 Spartans). But in the end, by August, Thermopylae had become the site of a great Persian victory.
For those countries currently in the cross hairs of a determined jihad – and this includes the United States, Israel, and much of Europe – there is no real need to worry about a contemporary Thermopylae. But there is considerable irony to such a "freedom from worry."
After all, from our present vantage point, preventing any form of classical military defeat will no longer assure our safety from either aggression or terrorism.
This means that we might now be perfectly capable of warding off any tangible defeat of our military forces, and perhaps even of winning more-or-less identifiable victories, but in the end we may still have to face extraordinary or even existential harm.
Our enemies don't need to fire a shot
What does this mean for our enemies? From their point of view, it is no longer necessary to actually win any war, or – in fact – to win even a particular military engagement. They needn't figure out complex land or naval warfare strategies; they don't have to triumph at "Thermopylae" in order to burn "Athens."
For our enemies, there is really no longer any reason to work out what armies call "force multipliers," or to calculate any pertinent "correlation of forces." Today these enemies can wreak havoc upon us without first firing a shot.
None of this is because we have necessarily done something wrong. It is simply the natural consequence of constantly evolving military and terrorist technologies.
Nor can this frightful evolution ever be stopped or reversed. On the contrary, our substantial current vulnerabilities in the absence of prior military defeat represent a present fact of strategic life that must be both acknowledged and countered.
To ensure that these vulnerabilities remain well below the existential threshold, however, we will soon have to build a new combat orthodoxy involving deterrence, preemption, and war-fighting options, together with bold new ideas for protective international alignments. We will also have to take a fresh look at arrangements for both active and passive defenses.
Nothing is more practical than good theory. This is especially the case in military planning, where adapting current strategy and tactics to antiquated assumptions can yield disaster.
Today we must recognize that our fragile civilization can be made to suffer enormously without first going down to thunderous defeat. We must adjust accordingly.
Safety from mutual weakness?
This would seem to be a prosaic recognition, but it is nonetheless true. With such truth, moreover, can come the corollary understanding that what is threatening for us is also threatening for our enemies. They, too, must now confront extraordinary homeland vulnerabilities in the absence of any prior military defeat.
Properly understood, this confrontation with a mutuality of weakness could compel our enemies to proceed with greater caution, but only if they were also primarily concerned with their own survival.
Notwithstanding President Obama's recent West Point rejection of the Bush doctrine's emphasis on unilateralism, similar incentives to preempt could also arise in the wake of any successful jihadist coup in already-nuclear Pakistan.
Louis René Beres is a professor of international law at Purdue University. He lectures and publishes widely on nuclear strategy and nuclear war. In Israel, Dr. Beres was chair of Project Daniel, commissioned to assess the threat to the nation of Israel from other states in the Middle East.