Those who speak of eternal peace coming in our time are not without a rationale. Longing for the prophecy of universal peace to be fulfilled, I can only sympathize with them.

It is utterly absurd to imagine France and Germany fighting again over Alsace and Lorraine when all of Europe is now a single state. The world which admired the British Empire two centuries ago shrugged at the senseless slaughter that occurred over the Falkland Islands; territorial conquests are not as fashionable as they used to be. Wars of robbery are for third-world states; in modern technological economies, hard goods that can be plundered are of little value compared to intellectual property and electronically registered financial assets. The value of human life has skyrocketed: at $5 million a head, another war on the scale of WWII would be prohibitively expensive. The threat of mutual assured destruction deters us from engaging in nuclear wars: despite the existential danger the Soviet regime felt from free-market ideas, it did not nuke the United States. On top of all this, humanism has changed the face of war: bombing enemy towns has become morally unacceptable, and sending one’s troops into urban combat has jacked up the cost of killing an enemy soldier to over $10 million, a price tags unbearable even to developed economies.

Yet, the arguments remain unconvincing. People in Christian Europe felt no less a common culture than today’s French and Germans. Indeed, people of common culture fight the bloodiest battles: in the Holocaust, ethnic Germans slaughtered fully assimilated “Germans of Mosaic persuasion,” and in Yugoslavia, various ethnic groups which have shared the same lifestyle for centuries slaughtered each other with a vengeance.
Peace in Western Europe has held for a mere seventy years; such intervals of peace, and even longer ones, are well documented throughout history. The Peace of Westphalia probably made Europeans no less jubilant than the Marshall Plan or the NATO treaty. The League of Nations stirred no less enthusiasm for eternal peace than the United Nations—and both have failed. The availability of inexpensive weapons has made wars in the Third World more common and lethal. Whether that effect will be temporary depends on the ability of African states to economically advance their citizens into affluence. Given the decreasing share of GDP attributed to unskilled labor, such a development is extremely unlikely.

Robbery has rarely been a principal reason for war. Wars bankrupt empires more often than they enrich them. Common Romans, citizens and legionaries alike, got food from their expeditions, but not much more than that. There was not much else to rob.

Territorial expansion is not an end, but an aggrandizement strategy. States swap and abandon colonies for political gains. Just as kings gave way to presidents, and king’s herds to trade surplus in electronic ban accounts, the means of aggrandizement could change. Some of the largest states are now dirt poor, Russia and China being the prime examples, and territory cannot be counted upon to bring respect. Why was territory important in the first place? Because it connoted a state’s power to acquire and hold land. That power can now be expressed in other ways: by obtaining nuclear potential, sending aircraft carriers to foreign shores, or threatening to abandon dollars in favor of euros as a reserve currency. States still fight over land—especially settled land—because losing some citizens sets a bad example for others by demonstrating that the state’s jurisdiction can be escaped. If there is a way to escape the state’s sovereignty, there is certainly a way to avoid taxation. States depend on credible monopoly over their citizens. The bottom line is, states still have plenty of reasons to fight.

But aren’t states themselves on their way out? Who knows. We have already seen this kind of globalization: the Catholic church became truly global, covering the entire civilized world, and then it broke apart into competing confessions. Or look from another angle: Very large states such as Russia can be meaningfully compared to near-global stateless entities like the EU. Ethnic and social groups there were distinct, though brought under the stately umbrella. When mobility was low, Russians felt like global citizens for all practical purposes: wherever they went, it was the same state. In such quasi-global states, civil wars are common.
Humanism was not unknown to previous generations. Some Christians once suggested that a better mode of war would be to battle the army, not the population. This principle was abandoned in the Napoleonic wars, when mammoth armies had to live off the land. In our times, a state armed with strategic bombers and ballistic missiles finds it hard to resist using them against an enemy’s soft targets. Terrorism may take us further in this dehumanizing direction. American military campaigns in Vietnam, Iraq, and Afghanistan, with the heavy toll they take on civilians, confirm that military action is not a great way to fight terrorists. The large-scale application of firepower is more economical, simpler, and satisfying, but it is not effective. Drones and guided munitions are fine against terrorists’ houses, but aerial bombardment remains a simpler way to force a local government to deal with its culprits.

Soldiering has become unfashionable, a refuge of the lower classes detested by liberal university graduates. But the trend is not new. For centuries, officers have shrunk from killing; over time their weapons became increasingly symbolic, like sabers in the age of firearms. Well-off Roman residents probably despised rank-and-file legionaries. Modern armies rely on cutting-edge technology and require less manpower than a century ago. The population explosion in the Third World provides them with a steady source of personnel.
Wars became prohibitively expensive because armies utilize the most advanced technology available, the cost of which rises faster than GDP. Except for short-term GDP explosions due to technological revolutions, military expenses seem to rise as a percentage of GDP. Nevertheless, advanced countries bear these expenses through unusually fast GDP expansion, and underdeveloped countries make do with low-tech warfare.

Human habits are not unchangeable. Our evolutionary history is very short compared to that of other mammals, and behavioral patterns adapt to circumstances. When marketers exploit our reciprocity, dishonest charities exploit our compassion, and politicians exploit our longing for wise leadership, one is tempted to surmise that our most ingrained habits will change considerably. An American man who calls the police when his neighbor makes a lot of loud noise after 11:00 pm is probably less martial than his Wild West or Neanderthal ancestors. Multiculturalism, the blank slate, and tolerance to evil have eaten away at the masculine fighting spirit, though we have yet to see whether that change will hold for many generations.
Nuclear deterrence suffers from a problem common to all deterrents: sometimes it just does not work. Bad intelligence underestimates the enemy, a hysterical ruler overestimates his troops, apocalyptical mullahs welcome doom, and religiously inspired terrorists hate Jewish Israel as much as they hate insufficiently Islamic Egypt, and would welcome their mutual destruction in a war. The stronger the deterrent, the longer the intervals between wars…but more devastating are the wars. The correlation is straightforward: stronger deterrence depends on more devastating weapons. In mathematics, this is known as zero multiplied by infinity: as the chance of war goes down to zero, the war’s destructive potential shoots up to infinity. The result of that multiplication is inherently unknown: it can be zero, infinity, or anything in between.
The chances of an irrational ruler coming to power in a developed Western state are next to nil, but nil happens. Germany was as advanced as states get when it elected the Nazis. Its economic downturn was temporary, and perhaps not so extreme by the standards of the Great Depression. Populations won’t support nuclear war, certainly, but neither did common Germans support the Nazi military drive. The population was universally apprehensive about the war until quick victories in Austria, Czechoslovakia, and Poland heated public opinion into all-out jingoism. Wars may be on their way out, but the ability to inflict devastation has increased accordingly.

Pauper states such as Iran, Pakistan, or North Korea cannot prosecute meaningful wars with the West. They can, however, prevail by asymmetrical means. For all its border control measures, the United States cannot prevent hundreds of backpack nukes from being smuggled and detonated. A smart attacker would target universities and commercial research facilities rather than military bases: taking out the top hundred universities and labs would cripple America more than any number of attacks on its military installations. With the happy demise of the Soviet Union, no country is strong enough to destroy the United States, but smaller European countries remain vulnerable. And even America, while not exactly destroyable, can suffer devastating damage.

Of the new weapons currently being considered, three types have the most potential to change the face of war. Inexpensive lasers can provide rogue states with sufficient defense against missiles and planes to safely attack developed countries. Tectonic and magnetic pulse weapons can enhance attack capabilities enough that poor states will find wars feasible. And we’ve yet to see military advances in nanotechnology, artificial intelligence, and biology.

We can be fairly certain about this: wars which involve developed states will be rarer, but more devastating and potentially apocalyptic.