War: What is it good for? (20 page)

In the seventh century
B.C.
, gangs of Scythians went into business for themselves, robbing anyone who came along and effectively taking over much of what we now call northern Iraq, Syria, and eastern Turkey. “Life was thrown into chaos by their aggression and violence,” the Greek historian Herodotus wrote, “because they rode all over, carrying off everything.” In the 610s, anti-Assyrian rebels hired Scythians of their own, and before the decade was out, the empire was in ruins. This, though, left the victorious rebels with the problem of what to do with the Scythians. They eventually solved it in the 590s (according to Herodotus, by getting the Scythian leaders drunk and murdering them).

The more Eurasia's empires grew, the more they found themselves facing a peculiarly modern problem: how to fight asymmetric wars around the edges of central Asia. In the late 1990s, when Osama bin Laden perpetrated his first massacres, the United States found no way to “neutralize”
(the preferred term) him in his Afghan lair except by firing million-dollar cruise missiles at terrorists' ten-dollar tents. Ancient empires, with their vast, ponderous infantry armies, found chasing bands of horsemen around the wilderness similarly difficult.

This was a matter not of Western versus non-Western ways of war but of agrarian versus nomadic ways. From Europe to China, the rulers of wealthy empires all faced more or less the same challenges in dealing with steppe horsemen, and by the age of Agricola they had all worked through every possible permutation for waging asymmetric war. Then as now, the obvious approach was preemptive war, and Persian kings sent a series of armies onto the steppes to chase down the Scythians. But pursuing the nomads into their hiding places, the Persians learned, could be almost as problematic as doing nothing, because infantry could not force nomad cavalry to fight if they did not want to. Sometimes preemptive wars paid off quickly, as in 519
B.C.
, when the Persians crushed a confederation that they called the Pointy-Hatted Scythians, but often they did not. In 530
B.C.
, nomads had killed King Cyrus, the founder of the Persian Empire, and annihilated his army. In 514, King Darius of Persia—after chasing the Scythians around the steppes for months without being able to catch them—only avoided the same fate by scrambling back across the Danube under cover of darkness.

Assyria and Persia were the first empires to become entangled with the steppes, but by the third century
B.C.
China was going the same way. In 213
B.C.
, the Qin First Emperor launched a preemptive war, annexing a great swath of the steppes in an effort to push the Xiongnu nomads away from his frontiers. But it brought the Middle Kingdom little joy: in 200
B.C.
the Xiongnu lured a Chinese army deep into the steppes and destroyed it completely.

In 134
B.C.
, the emperor Wudi tried preemptive war again and half a dozen times over the next fifteen years sent armies hundreds of thousands strong into the steppes. Few of his men returned, and the costs wiped out the budget surpluses his cautious predecessors had accumulated, driving the government deep into debt. But despite spending so much, Wudi—like Darius—never did get his decisive battle with the nomads.

From Athens to Chang'an, intellectuals denounced preemptive war as disastrous. But in another peculiar parallel with modern experiences, in the long run it proved surprisingly difficult to tell who had won the preemptive wars, or even when they were over. The costs in blood and treasure
had been terrible, but the Scythians never again threatened Persia after 513, and Xiongnu raiding had declined sharply by 100
B.C.

The conclusion emperors eventually reached was that the hard power of expensive expeditions onto the steppes worked best when combined with softer, albeit still pricey, techniques. The most popular was containment, which usually meant building walls to keep nomads out. The most famous, the Great Wall of China, goes back to the 210s
B.C.;
the wall that Hadrian built in the 120s
A.D.
, mentioned at the beginning of this chapter, was its distant cousin. Walls could not keep nomads out altogether, but they did at least channel where the horsemen came in.

The most successful (or, perhaps, least unsuccessful) strategy was bribery. Nomad raids killed a lot of people and lowered the empires' tax take, so why not just pay nomads not to raid? As long as bribes cost less than preemptive war, protection money was a win-win-win proposition—the emperors saved cash, the peasants in the borderlands saved their lives, and the nomads saved themselves a lot of trouble. Two thousand years on, bribery retains its appeal in asymmetric warfare: by handing out $70 million in cash to Afghan warlords in 2001, the CIA also saved a lot of money, lives, and trouble.

There is a saying in Chicago that an honest politician is one who, when you buy him, stays bought, but expectations are lower in asymmetric wars. The Afghan commander who took $10,000 in December 2001 to guard escape routes from the Tora Bora Mountains, only to let al-Qaeda fighters through when they offered him more, would have fit right in on the ancient steppes. Scythians and Xiongnu regularly took payoffs and then raided anyway. Bribery, it turned out, was the worst way to deal with nomads—except for all the other ways. Persian and Chinese strategists found that handouts worked best as part of a package of carrots and sticks. A stream of sweeteners combined with the occasional massive, violent, preemptive war could more or less keep the peace.

Combining all these tricks, rulers in the last few centuries
B.C.
learned to manage their frontiers. They turned their relationships with the steppe nomads into something resembling bad marriages, in which the partners could live neither with nor without each other. When an empire was strong, it could impose a settlement on part of the steppes and keep violence within tolerable limits; when it was weak, it had to pay more and suffer more.

The only way to keep the upper hand, every empire discovered at some point in the millennium between roughly 500
B.C.
and
A.D.
500, was to
beat the nomads at their own game. This meant that emperors had to leaven their huge infantry armies with more and more cavalry. Historians who think there is a Western way of war rooted in ancient Greek culture often see fighting from horseback as typical of Eastern evasiveness, while fighting on foot is the hallmark of Western values. In reality, though, the great shift toward cavalry between 500
B.C.
and
A.D.
500 was driven by geography, not culture. Empires whose frontiers ran right up to the steppes shifted toward cavalry relatively soon after 500
B.C.;
those that were shielded by mountains and forests shifted later, and less completely. But, willingly or not, all the empires in the Old World's lucky latitudes moved in the same direction.

Not surprisingly, the shift began in Persia, the empire most exposed to nomadic raids. When Darius chased the Scythians around Ukraine in 514
B.C.
, almost all his men were walking, but by 479, when the Persians fought the Greeks at Plataea, they relied almost as much on cavalry as on infantry. And in 334, when Alexander the Great invaded Persia, the empire looked almost entirely to riders for victory. China, the next-most-exposed empire, was also the next to move down the riding trail. Emperor Wudi raised huge mounted forces before launching his preemptive wars. In 110
B.C.
he had 180,000 horsemen on his payroll, making up one-third of the army and costing twice as much to feed each year as the entire empire paid in taxes. India, largely shielded from the steppes by the Himalayas and the Hindu Kush, was less exposed, and between the fifth and the second centuries
B.C.
its kings felt safe sticking to what they knew. Head-on clashes of armored elephants still won battles, with horsemen doing little more than covering the elephants' flanks—until another oddly modern development shifted the ground under their feet.

In 1954, faced with mounting demands to do something about the spread of communism in Southeast Asia, President Dwight Eisenhower warned America about “what you could call the ‘falling domino' principle. You have a row of dominoes set up,” he explained, “you knock over the first one, and what will happen to the last one is the certainty that it will go over very quickly. So you could have a beginning of disintegration that would have the most profound influences.”

Whatever its strengths or weaknesses as an analysis of 1950s Indochina, this is an excellent description of the steppes in the first century
B.C.
As Han China's huge cavalry armies began getting the better of the Xiongnu, many of the nomads migrated westward into lands where the Yuezhi peoples had traditionally grazed their flocks. The terrified Yuezhi then
moved still farther west, which took them into Scythian territory. As the next domino fell, the Scythians (called Shakas in India) moved south through what is now Afghanistan, crossed the Khyber Pass, and descended into the Indus Valley. By 50
B.C.
the Shakas had overrun much of northwest India.

A century later—after more half-forgotten cavalry wars on the steppes—the Yuezhi followed the Shakas over the Hindu Kush. Pushing the Shakas deeper into India, the Yuezhi conquered a huge domain stretching from modern Turkmenistan to the middle Ganges, known to historians as the Kushan Empire. The Kushans prospered mightily, becoming one of the great cavalry powers of the day. By the second century
A.D.
, their fearsome mounted archers, commemorated in countless sculptures in what are now Afghanistan, Pakistan, and northern India, controlled the Silk Roads linking Rome and China. The Kushans even fought their own preemptive wars, including one against a Han expedition to Afghanistan.

India's experience revealed the hard fact that revolutions in military affairs are irresistible. As dominoes fell and agrarian empires came under pressure, the empires could either turn themselves into cavalry powers, as Persia and China did, or, like India, be overrun by nomad groups that were already cavalry powers—in which case the invaders would turn the society they conquered into a cavalry power anyway. The choices rulers made might speed up or slow down the process, but the paradoxical logic of war always won in the end.

In the same years, the Han Empire in China (which had started India's woes by setting dominoes tumbling across the steppes) learned an even harder fact—that the long story of the empires' entanglement with the steppes was now reaching its culminating point. China had been fighting Xiongnu nomads along its northern frontier since 200
B.C.
, but all had been quiet on its western front, which was shielded from the steppes by a hundred-mile-thick band of mountains and forests. But that changed when the Xiongnu migrated around 50
B.C.
While one branch of the confederation moved west and toppled the dominoes that drove the Yuezhi and Shakas into India, a second branch moved south, plundering the Qiang farmers on China's western border.

For decades, the Qiang had shielded China by fighting bitter frontier wars against hit-and-run nomad raids, but in the first century
A.D.
, caged between the nomads and the Han imperial frontier, the Qiang began to form their own governments. Large, well-organized groups of Qiang moved into Han territory to get away from the Xiongnu, fighting the empire's
troops if they had to. The Qiang were changing from a shield into a sword, thrusting at the empire's vitals.

Chinese border officials could see where things were heading. “Recently,” one observed in 33
B.C.
, “the Western Qiang have guarded our frontier, and thus come into regular contact with Han people”; however, his report continues, as more Qiang moved into Han territory, “minor officials and greedy commoners have robbed the Qiang of cattle, women, and children. This has provoked the Qiang's hatred, so they have risen in rebellion.”

In the first century
A.D.
, the Han lost control of their western frontier. In
A.D.
94, 108, and again in 110, great rebellions/invasions (it was hard to tell the two apart) got out of hand. The borderlands spiraled down into violence. “Even women bear halberds and wield spears, clasp bows in their hands and carry arrows on their backs,” an official named Gong Ye lamented.

At the far western end of Eurasia, a similar set of facts was about to end Agricola's productive war and bring Rome to the same culminating point. The Roman Empire had long been shielded from the steppes by a zone of Germanic herders and farmers that was even thicker than the Qiang zone on China's western frontier, but here, too, steppe migrations now turned the shield into a sword aimed at the empire's heart.

The motor might have been the Sarmatians, nomads living along the Don River, who began moving west in the first century
A.D.
They were a fierce lot: according to Herodotus, they descended from the Amazons, and no Sarmatian woman was allowed to marry until she had killed a man in battle. Be that as it may, their distinctive combination of light and heavy cavalry, with horse archers disrupting enemy lines before armored riders charged home with spears, proved devastating. It was the arrival of a Sarmatian tribe called the Iazyges on the north bank of the Danube in the early 80s
A.D.
that prompted Domitian to recall Agricola's troops from Britain, and the spread of other tribes across eastern Europe caused chaos for everyone whose path they crossed.

In the first two centuries
A.D.
, warmer weather brought population growth to Europe, increasing caging among German farmers. Consequently, any tribe that tried to get out of the Sarmatians' way immediately set off desperate wars with neighbors determined to defend their fields. The Germans living nearest the steppes copied their tormentors and started fighting from horseback, and even those Germans farthest from the steppes adopted better weapons and tactics. Under the pressure of war,
chiefs turned into kings who centralized power, extracted taxes, and organized real armies.