War Will Be War: No matter the era, no matter the weapons, the same old hell.

War is eternal. It is part of the human condition; it is, as Heraclitus wrote, "the father of us all." This is the first thing we must remember whenever discussion turns to "revolutions in military affairs." Some things will change, but the underlying laws and lessons that have shown themselves over millennia of warfare remain true about wars today -- and wars tomorrow.

One of these key truths is that culture largely determines how people fight. The degree to which a society embraces freedom, secular rationalism, consensual government, and capitalism often determines -- far more than its geography, climate, or population -- whether its armies will be successful over the long term. Israel today is surrounded by a half-billion Middle Eastern Muslims -- and has little to fear from their conventional militaries. Kuwait and Saudi Arabia have some of the most sophisticated weapons in the world; Saddam Hussein's Iraq still fields one of the largest armies; Iran boasts of spirited and fiery warriors. Israel -- not to mention the United States -- could vanquish them all. This appraisal is simply a statement of fafact; it is neither triumphalist nor ethnocentric. It recognizes that if -- for example -- Iraq were to democratize, establish a Western system of free speech and inquiry, and embrace capitalism, then Iraq too, like Taiwan or South Korea, might well produce a military as good as Israel's.

Another key truth is that overwhelming force wins. Much has been made of the latest epidemic of terror and suicide bombing -- as if hijackers with tiny budgets could overcome opponents who spend trillions on defense. But history proves otherwise: Frightful terrorists such as the Jewish sicarii of Roman times, the ecorcheurs of the Hundred Years' War, and the Mahdi's dervishes in 19th-century Sudan usually petered out when they were faced with an overwhelming military force that was fighting for attractive ideas. Guerrillas, after all, require money, modern weapons, and bases in countries with friendly governments. Superpowers -- such as imperial Rome and contemporary America -- have the wherewithal to deny the terrorists access to much of this necessary support. September 11 revealed the complacency and carelessness of a democratic and affluent United States; but the relative absence of follow-up attacks -- as America systematically eradicates al-Qaeda 7,000 miles away from its shores -- suggests that a powerful state can more than handle stateless terrorists.

It can do so because a Green Beret fighting terrorists in a cave can rely on a multibillion-dollar carrier battle group to bomb the terrorists; all he has to do is call in his GPS coordinates. This is the West's edge; and a chief military challenge of the 21st century, therefore, will be not terrorists per se, but the degree to which globalization brings the Western way of war to the much larger non- West.

During the Clinton administration, it was feared that exported weapons and pilfered expertise might soon bring China technological parity with America. But no one is yet sure whether the simple possession of sophisticated arms amounts to military equivalence -- without the accompanying and more fundamental Western notions of discipline, market logistics, free-thinking command, and civilian supervision.

An F-16 fighter jet does not exist in a vacuum: A literate middle class is needed to produce mechanics who can service and modify it; freedom of scholarship is required if designers are going to update it; and an open society is necessary if the plane's sophisticated controls are going to be operated by competent, motivated, and individualistic pilots. As a rule, Israeli pilots proved deadly against Syrian jets in Lebanon -- but Iraqis in advanced Russian aircraft would fly into Iran rather than fight American planes during the Gulf War.

Another example: There are probably plenty of Stinger missiles still hidden away in Afghanistan, but it has been nearly two decades since they were built -- and Afghans have not modified or updated them to meet the intervening efforts to neutralize their effectiveness. In the short term, such subtle differences don't seem important. But in the long run -- as we have seen in the Falklands, the Arab-Israeli wars, the Gulf War, and Afghanistan -- they can trump numerical superiority, tactical genius, and heroism itself. There is a reason that Arafat, not Sharon, was surrounded in his bunker: It is not terrorists, but tanks - - and the quality of men in them -- that decide the preponderance of ststrength in the Middle East.

This is true not just in the Middle East but everywhere. The education system, therefore, and the preservation of an open society with a common Western culture are as valuable for our national security as our impressive military hardware. If the degree of Westernization in the next few years will often determine which armies win and lose, history also teaches us that with affluence and personal freedom comes a sense of laxity. The fact that a society can, in theory, defeat its enemies does not ensure that it will indeed do so. The unwillingness of affluent individuals to accept the responsibilities of defense is a common theme in Roman authors as diverse as Livy and Juvenal.

We see evidence of this sort of smugness in today's Europe, whose elites snicker at America's muscular response to September 11, whose taxpayers are unwilling to shoulder defense expenditures that might imperil their lavish social spending, and whose society has embraced a utopian view that war itself is simply outdated and can be eliminated by properly educated diplomats. (This is in stark contrast to such powerful countries as China and India, which have lately begun to adopt elements of the Western way of war: They maintain large defense establishments and have highly nationalistic citizenries that are not yet affluent or secure enough to trust that war is a relic of the past.)

The U.S. doesn't share Europe's anti-military bias, but it has its own problems. In a society in which a $50,000, three-ton, gas-guzzling monstrosity is required to transport safely a soccer mom and her twelve-year-old a few blocks to the practice field, it should come as no surprise that the military, too, has an "SUV syndrome": the embrace of expensive gadgetry and machines to ensure at all costs the safety of the individual combatant. The more that technology and science can ameliorate the human condition of the average American citizen, and prolong life by conquering the age-old banes of accident, disease, and famine, the more our cultures expect that our soldiers, too, will avoid wounds and death. The anticipation that we shall all die at 90 in our sleep -- peacefully and without pain -- results in an array of social and cultural limitations placed upon the conditions of battle. Societies that are affluent and free expect their soldiers to be able to kill thousands of enemies who are neither -- and without incurring any deaths in the process. In Afghanistan, our military has chosen repeatedly to be wary about exposing our own men to danger -- even when it meant that dozens of dangerous al-Qaeda and Taliban would escape.

Another eternal law of war is that the advantage keeps shifting, back and forth, between defense and offense. For centuries the methods of defense -- whether stout ashlar-stone walls in the pre-catapult era, or knights in the age before the crossbow -- trumped the effectiveness of most attackers. Today, however, destruction is easy -- thanks to automatic weapons, precision bombing, and nuclear arsenals. But we may be witnessing the beginning of a shift back toward the defense: Breakthroughs in impenetrable light plastic and composite materials may well make our infantrymen as well protected against projectiles as yesterday's hoplites. We have seen this already in Afghanistan, where unharmed American soldiers have found spent slugs in their ultramodern flak vests.

For all the lethality of bunker-busters, daisy-cutters, and thermobaric bombs, reinforced caves -- outfitted with space-age communications and supplies -- seemed to protect al-Qaeda warriors well enough to force our designers back to the drawing boards to discover new ordnance that might bore through yards of such rock. On the intercontinental level, the once ridiculed concept of missile defense is no longer so ridiculous, and only a few years rather than decades away -- raising the eerie and once inconceivable thought that a missile exchange might not result in horrendous carnage.

Tomorrow's wars will also prove that other historical rules remain valid. In the 1970s, for example, it was popular to scoff that carriers were simply floating targets that would "last about a minute" in a war with the Soviet Union. But any weapons system that is mobile, capable of sending out dozens of planes either to attack any type of enemy or to defend their mother ship, has timeless value. Despite its massive size, nuclear propulsion, electronics, and superior design, today's Enterprise is not all that different in form and function from its eponymous ancestor that fought at Midway. Why? Because a floating airstrip is a perfect and timeless weapon, one not dependent on volatile host countries; it is forever mobile, lethal at great distances, and eternally useful because it can be updated to reflect new technologies.

By the same token, submarines that twenty years ago were deemed the wave of future naval warfare have played a less prominent role in the post-Cold War era; their nuclear arsenals and near-miraculous stealth have proved of little value in the asymmetrical Gulf War or the air campaign against Serbia. It would, however, be a mistake to dismiss as superfluous any weapon that can strike without being seen: An array of conventionally armed submarines has already been modified to fire dozens of cruise missiles at distant inland targets, and there's no reason submarines could not be posted off the coast of Iran or North Korea with a full arsenal of anti-ballistic missiles to ensure that any nukes launched from those countries would be shot down a few thousand feet from their launch pads.

The conventional wisdom of the pundits will always be evanescent. We must not be hoodwinked by their presentism into thinking that a new weapon or a new theory has "reinvented" war. It cannot happen. There will be new technologies and new approaches to fighting -- but we need to see how they fit into age-old military realities.

The first such reality is that war will not be outlawed or made obsolete. This idea is a spasm of utopian thinking on the part of elites; its only result is to get millions of less educated and less affluent innocents killed. War cannot be eliminated entirely, only avoided by deterrence. "He who wishes peace should prepare for war," runs the ancient wisdom -- and it remains true today. When America had a "Department of War," no more Americans were killed overseas than in the period after its name was changed to the less bellicose "Department of Defense" -- reminding us that we can repackage and rename conflict through euphemism and good intentions, but never really alter its brutal essence.

The second key reality is that war is not merely a material struggle, but more often a referendum on the spirit. No nation has ever survived once its citizenry ceased to believe that its culture was worth saving. Themistocles' Athens beat back hundreds of thousands of Persians; yet little more than a century later Demosthenes addressed an Athens that had become far wealthier -- and could not marshal a far larger population to repulse a few thousand Macedonians. Rome was larger, far more populous, and wealthier in A.D. 400 than in 146 B.C. -- but far more unsure about what it meant to be a Roman, and confused about whether being Roman was better than, or merely different from, being German or Persian. France, which stopped the Germans at Verdun, a quarter-century later let them romp through the Ardennes in six weeks. The more complex, expensive, and lethal our weapons become, the more we must remember that they are still just tools, whose effectiveness depends on the discipline, training, and spirit of their users.

If the United States continues to believe that its culture is not only different from, but better than, those of the rest of the world -- and if it believes that its own past pathologies were symptoms of the universal weaknesses of men, rather than lasting indictments of our civilization -- we will remain as strong as we were during the wars of the 20th century. In contrast, if we ever come to believe that we are too healthy, too sophisticated, and too enlightened ever to risk our safety in something as primitive as war, then all the most sophisticated weapons of the 21st century will not save us when our hour of peril comes. And, as September 11 reminds us, that hour most surely will come.