allies, Thebes and Sparta, quickly turned on each other in squabbles
over booty, the treatment of defeated Athens, and respective spheres of
influence. Indeed, for most of the ensuing half-century (403–362), the
two rivals were in a near-constant state of conflict marked by pitched
battles, frequent Spartan invasions of Boeotia, and brief armistices.
Contemporaries largely viewed their early struggle as a sometimes lop-
sided contest between a traditionally superior Spartan phalanx and an
upstart Theban infantry hitherto considered formidable, but hardly an
instrument capable of projecting Theban power beyond the confines
of a cultural Boeotian backwater with a questionable history.4
The on-again, off-again decades-long struggles, however, took a radi-
cally different turn in 379 BC. In that year a remarkable group of Theban
democrats overthrew the ruling oligarchs under Leontiades, who was
propped up by Spartan overseers. In place of oligarchy, the reformers
instituted a Boeotian confederate democracy freed from outside influ-
ence and bent on ensuring a permanent end to Spartan meddling in the
affairs of the Greek city-states. Not only did the ongoing war between
the two rivals now assume a new ideological dimension, democracy
versus oligarchy, but the conflict was energized by this new group of
Theban firebrands, who were not quite doctrinaire in accepting tradi-
tional notions of a balance of power between the city-states. Instead,
led most notably by Pelopidas and, later, Epaminondas, Theban demo-
crats came to the fore determined to eliminate permanently the source
of the Spartan threat.
In reaction, for much of the next eight years the Spartans were
bent on revenge for their own expulsion from Boeotia. King Agesilaus
rightly feared that the new Boeotian democracy under Epaminon-
das was no longer just a rival polis but rather a unique revolutionary
agent of change that could eventually threaten Sparta’s own interests
in the Peloponnese, as well as refashion altogether the traditional
The Doctrine of Preemptive War 95
autonomous network of small individual city-states into larger and far
more hostile democratic blocs and confederations. As a result of these
apprehensions, between 379 and 375, on at least four occasions Spartan
kings invaded, or attempted to invade, Boeotia to dismantle its new
democratic Boeotian confederation.5
Aside from occasional military alliances with Athens, the Boeotians
turned to a variety of both passive and active strategies to blunt these
serial Spartan offensives. At various times they resorted to erecting an
extensive wooden stockade around their most fertile farmland. Some-
times they harassed the invaders with both light-armed and mounted
patrols. On rarer occasions they managed to draw them into skirmishes
and small pitched battles, such as the surprisingly successful engage-
ment at Tegyra in 375.
This Theban democratic and Spartan oligarchic rivalry initially
played out in limited fashion, according to traditional Greek protocols
of annual invasions in which the invader tried to harm the agricultural
infrastructure of the invaded state. While King Agesilaus, the archi-
tect of the Theban invasions, almost succeeded for a season or two in
bringing near famine to Thebes, and had established forts in a number
of Boeotian cities—Plataea, Orchomenos, Tanagra, and Thespiae—the
Spartans in their nearly decade-long efforts failed to end Theban demo-
cratic control of Boeotia. These years of serial and inconclusive fight-
ing in Boeotia explain not only Epaminondas’s later radical decision to
meet the Spartans in pitched battle at Leuctra but also his subsequent,
even larger gamble to attack Sparta itself. At some point in this decade,
Epaminondas apparently saw there would be no end to the normal
pattern of serial invasion and battle other than an end to Sparta as the
Greeks had known it for the prior 300 years.6
The Invasion of Winter and Spring 370–369
The pulse of this long war of attrition changed radically a second time
sometime in midsummer 371, when the Spartans broke the general ar-
mistice of 375 and once again invaded Boeotia. But this time, under
the leadership of the Theban general Epaminondas, the outnumbered
Boeotian army at last chose to engage decisively the Spartan invaders
96 Hanson
in a dramatic pitched battle amid the rolling hills of Leuctra, not far
from Thebes itself. There, in brilliant fashion, the Boeotian army nearly
wrecked the invading force, killed the Spartan king Kleombrotos and
about 400 of his elite 700 Spartan hoplites, as well as hundreds more of
allied Peloponnesians, and sent the scattered survivors back home in
shame and defeat, at once redefining the strategic balance of the Greek
city-states and presaging a permanent end to what had been nearly an-
nual Spartan invasions in the north.7
Most prior decisive victories in Greek hoplite battle—First Coronea
(447), Delion (424), or First Mantineia (418)—had led to a regional ces-
sation of major fighting for a few years. But the win at Leuctra, despite
its decisive nature, soon led to a resurgence of, not an end to, The-
ban–Spartan hostilities, and proved to be a precursor of a vast reorder-
ing of the Peloponnese. If the Sicilian expedition of 415–413, in which
some 40,000 imperial Athenian soldiers and allies were lost, captured,
or killed, ended the dream of an expanding Athenian empire, the loss
of about 1,000 Peloponnesians and the humiliation of the legendary
Spartan military prowess at Leuctra had a similar effect of ending the
idea of Spartan expansionary policy and questioning the stability of its
very rule beyond the vale of Laconia.
About eighteen months after the battle (which occurred in July 371
BC), during December 370–369 BC, the general Epaminondas convinced
the Boeotian leadership to embark on a preemptory strike to the south.
The ostensible reason for intervention was a call for help to the Thebans
from the newly consolidated Arcadian city of Mantineia to ward off the
threat of constant Spartan invasion by King Agesilaus. Epaminondas
seems to have concluded that even after Leuctra, the Spartan army still
threatened large democratic states, and that it would only be a matter
of time until the Spartans regrouped and attempted yet another annual
incursion into Boeotia. The timely invitation from the Arcadians and
other Peloponnesians to intervene on their behalf seems to have galva-
nized Epaminondas into envisioning an even larger—and final—plan to
end the Spartan hegemony of the Peloponnese altogether.8
Epaminondas’s huge al ied army included thousands of Pelopon-
nesians who joined the invasion at various places south of the Corinthian
Isthmus, among them perhaps some of those Peloponnesians spared
The Doctrine of Preemptive War 97
over a year earlier at Leuctra. The march fol owed a nearly 200-mile
route into the heart of the Spartan state, a legendarily inviolate land-
scape said to have been untouched by
enemies for some 350 years. After
ravaging the Spartan homeland and bottling the Spartan army up inside
the city across the icy Eurotas, the Boeotians failed to storm the acrop-
olis. Instead, after burning the Spartan port at Gytheion twenty-seven
miles to the south, Epaminondas’s Boeotians, along with some contin-
gents of their victorious Peloponnesian al ies, decided to head west in
midwinter across the range of Mt. Taygetos into Messenia, the historical
breadbasket of the Spartan state, where indentured serfs, known as hel-
ots, supplied foodstuffs and manpower for the Spartan state.9
The Boeotians probably descended from the uplands of Taygetos
sometime after the first of the year 369 BC, routed the Spartans from
their rich protectorate in Messenia, freed most of the helots there, and
helped to found the vast citadel of Messene. Before they departed the
following spring, Epaminondas had ensured a new autonomous and
democratic state of Messenia, its fortified capital at Messene now es-
sentially immune from Spartan reprisals. And by the time Epaminondas
had marched home, he had humiliated the Spartan state and ended its
parasitical reliance on Messenian food, a relationship essential to free-
ing up the Spartan warrior-citizen caste to focus on warfare. His dream
of an anti-Spartan axis anchored by Messene, the new fortified Man-
tineia, and the rising Megalopolis seemed to be approaching reality.10
The remarkable invasion itself was an anomaly in a variety of ways.
Early fourth-century Greek armies, even after the innovative tactics
that emerged during the Peloponnesian War (431–404), still usually
marched in late spring, preferably around the time of the grain harvest,
to ensure good weather and secure adequate rations in the field, as well
as to have a better chance at burning the ripening and drying wheat
and barley crops of the invaded. Such seasonal armies usually were
not absent for more than a few days or weeks because of their own
harvesttime obligations. As nonprofessionals, they had little ability to
provision themselves for extended stays abroad, whether judged by dis-
tance or by time away from home. Usually the target was a nearby en-
emy army or the agricultural resources of a neighboring hostile power
rather than the utter defeat of a more distant adversity and the end of
98 Hanson
its existence as an autonomous state. Total war intended to destroy a
relatively large state was rare.11
Epaminondas in remarkable fashion ignored most of such past pro-
tocol of internecine Greek warfare. He chose to leave Thebes in De-
cember, when there were no standing crops in the field, the roads were
muddy, and his one-year tenure as Boeotarch was set to expire within
days of his departure at the first of the Boeotian year. He may have
remained gone for as long as five to six months, until near late spring
harvesttime, 369. And Epaminondas faced certain trial on his return for
violating the terms of his one-year tenure of command. His aims were
not just the defeat of the Spartan military or even occupation of the
Spartan acropolis but apparently, either before or after he arrived in the
Peloponnese, a sustained effort to end the Spartan state itself.12
Clearly, there was a sense of urgency in his decision to wage such an
unprecedented preemptive war in midwinter, and that anomaly raises
a number of critical questions. Was such a preemptive strike unusual
in Greek history? What were the larger aims of Epaminondas, and did
he achieve his long-term objectives? Or did his Boeotians simply widen
an already long and costly struggle between two former allies? Was
such a preemptive war sustainable, given domestic political opposition
at home and the finite resources available for such costly and lengthy
commitments abroad? And does the Theban experience with preemp-
tive war and spreading democracy have any lessons for the present?
Before answering those questions, it should be noted again that
while the classical world considered Epaminondas among its most
preeminent heroes, we have very little information about his career,
and we know even less about the details of his great first invasion of
the Peloponnese and the founding of Messene. There are no surviv-
ing in-depth ancient speeches that reflect his plans, or much editorial-
izing on the part of historians about his intentions. Xenophon, the only
extant contemporary historian of the era who chronicled the Theban
invasions, either did not appreciate the magnitude of Epaminondas’s
achievement (Epaminondas is not mentioned by name in the Hellenica
until his final campaign and death at Mantineia; see 7.5.4–25) or har-
bored a generic prejudice against all things Theban. Plutarch’s life of
Epaminondas is lost. As a result, we rely on bits and pieces in Diodorus,
The Doctrine of Preemptive War 99
Plutarch’s Pelopidas and Agesilaus, Pausanias, and later compilers such
as Nepos. To a large degree, the motivations and aims of Epaminondas
are difficult to recover and remain seemingly iconoclastic and not easy
to fathom.13
Preemptive and Preventive Wars
Both preemptive and preventive wars in varying degrees are justified as
defensive acts, and thus supposedly differ from wars of outright aggres-
sion or blatantly punitive strikes. No one, for example, suggests that
the Persian king Xerxes invaded Greece in 480 to prevent an impending
major Hellenic attack on the Persian Empire. Nor did Alexander the
Great cross the Hellespont to stop Darius III from striking Greece first.
For all the talk of “the brotherhood of man,” he was bent on aggres-
sion, plunder, and conquest, under the banner of paying the Persians
back for more than a century of meddling in Greek affairs.
Despite the Athenian rhetoric of 415, on the eve of the disastrous Si-
cilian Expedition, about past grievances and future dangers emanating
from the West, such as Alcibiades’s warning that “Men do not rest con-
tent with parrying the attacks of a superior, but often strike the first blow
to prevent the attack being made,” few Athenians probably believed the
pretense that the expedition against Syracuse anticipated, either in the
short or the long term, a Sicilian attack on the Athenian Empire. In-
stead, this too was a clear case of imperial aggression, aimed at finding
strategic advantage during a hiatus in the Peloponnesian War. The list
of such unambiguously aggressive wars could easily be expanded in the
Greek world and would include such episodes as the Persian invasions
of Greek territory in 492 and 490, Agesilaus’s attack on Asia Minor in
396 to liberate the Greek city-states of Ionia, and Philip’s descent into
Greece in 338, which culminated in the Greek defeat at Chaeronea.14
In contrast, among the so-called defensive wars, preemption is usu-
ally distinguished from preventive war by the apparent perception—or
at least claim—of a credibly imminent threat. The reality of that as-
sertion determines whether an attack is generally accepted as genu-
ine
ly defensive. When a state—often one considered the traditionally
weaker side—preempts and strikes first, it is supposedly convinced that
100 Hanson
otherwise an existentially hostile target itself will surely soon attack,
and will do so with much greater advantage. Again, this initial aggres-
sion of preemptive wars is usually framed as defensive in nature, if the
presence of a looming danger is generally recognized. And the argu-
ment is strengthened further if there is a past history of conflict be-
tween the two belligerents.15
Truly preventive wars, on the other hand, such as the Iraq War
of 2003 or the German invasion of the Soviet Union in June 1941, are
much more controversial. The attacker—now usually assumed to be
the stronger power—claims that time will increasingly favor the geo-
political status of an innately aggressive and strengthening adversary
that sooner or later might strike and change the status quo. Thus the
instigator believes that its own inevitably declining position vis-à-vis a
belligerent rival can be aborted by weakening or eliminating a potential
threat before such an action proves less promising or impossible in the
future. But because the imminence of danger is usually far less likely to
be universally recognized than is true in cases of preemption, and since
the initiator is usually the currently more militarily powerful, preven-
tive wars are far more often easily criticized as wars of aggression.
The Japanese, for example, convinced no one that their “preventive”
Pearl Harbor strike of December 7, 1941, was aimed at weakening an
enemy that otherwise would only have one day become stronger in an
inevitable American-Japanese war to come. Most felt it was the first step
in a westward expansion across the Pacific to augment the preexisting
Japanese-led Asian Co-Prosperity Sphere. In turn, the United States did
not seek to strike Japan first, out of fear that such an attack might not
be seen as an understandable preemptive war to ward off an imminent
Japanese aggression but rather at best as a more controversial preven-
tive war that would be denounced by many isolationist Americans as
optional, bellicose, and imperial rather than defensive and necessary.
A beleaguered Israel, to general world approval, preempted by mere
hours its Arab enemies during the Six-Day War of June 1967 by striking
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