This article is taken from the March 2025 issue of The Critic. To get the full magazine why not subscribe? Right now we’re offering five issues for just £10.
In a world where nuclear annihilation is possible, how much should we fear the danger of war escalating?
The question has resurfaced with the conflict in Ukraine. It last seriously arose for the West during the Korean War of 1950–53 and the Cuban Missile Crisis of 1962. In Korea, Cuba and now Ukraine, a breed of “maximalist” war hawks offer the same answer: “not much”.
Indeed, they argue our anxiety is the problem. They lambast the policy of blunting Russian aggression whilst taking steps to avoid going to the brink. They accuse doubters of being feckless appeasers, branding policies short of maximalism as cowardly, irrational surrender to Russian coercion. It is folly, they say, to moderate Western efforts against Moscow, since we are already “at war” with Russia. To take Vladimir Putin’s nuclear threats seriously is to fall prey to “self-deterrence”.
Since Putin’s “red lines” have proven false before, we should treat them all as bluffs. Shielded by our arsenals, “we” can refuse to be deterred, confident Russia will choose to be deterred. In the words of military historian Eliot Cohen, “What should we do in response to Putin’s nuclear bluster? Follow John Paul II’s wisdom: ‘Be not afraid.’”
Should we not be afraid? Minds of another, tough-minded tradition beg to differ. The Greek word for “danger” appears more than 200 times in Thucydides’s history of Athens’s fratricidal war against Sparta that wrecked its power and ravaged the Hellenic world. Danger, for the Athenian admiral, historian and exile was all around. The impulse of fear, intertwined with danger and chance, is paramount in Thucydides’s telling of the story.
Nature intervened repeatedly to defy the efforts of the warring parties for control, through eclipses, floods, plagues, earthquakes and the confusions wrought by fighting in the dark of night.
In Thucydides’s hands, fear was both a cause of things and a necessary part of judgement. It had useful and pernicious forms. As the classicist Bret Deveraux notes, fear could work as the unreasoning and self-harming phobos, or it could take the shape of deos, a general word for desiring to avoid a dreaded thing happening. Both war itself and complacency about it were threatening. Military preparation, adequate fortifications and alliances were necessary for survival. Still, getting into conflict could also end everything. Defeated city-states were often demolished and, when not destroyed, stripped of their walls and subjugated.
Since realists value military power as the main currency of international politics, they are easily confuse with unreflective militarism
War’s uncertain course runs through Thucydides’s account. “Think, too, of the great part that is played by the unpredictable in war,” he has Athens’s envoy warn the Spartans before the gloves come off. “The longer a war lasts, the more things tend to depend on accidents. Neither you nor we can see into them: we have to abide their outcome in the dark.”
Thucydides was an early thinker in the pessimistic tradition of international politics known as “realism”. Realism has appealed through time and space, emerging in ancient India, medieval China, Renaissance Florence and beyond. Realists are not identical, yet they typically share a quality which can often be overlooked: most realists fear war, the very thing they believe defines the world.
Since realists value military power, backed by economic strength, as the main currency of international politics, observers can easily confuse them with unreflective militarism. After all, realists believe the world is an inherently anarchic, dangerous place without a central, global authority on hand to rescue us. This state of ultimate solitude puts a premium on self-help and power, especially coercive power. But typically, whilst realists value military strength, they view it nervously and sense the need to limit it.
Niccolò Machiavelli, author of The Prince and also an exile, stressed the need to anticipate manifold dangers, to mix “force” with “prudence”, such as the dangers of over-reliance on mercenaries, the beguiling forecasts of manipulative exiles or the hazards of launching hostilities without popular backing.
Even Otto von Bismarck, a figure famous for embracing blood, iron and realpolitik, strove to link violence to achievable goals, taking care that enemies were first isolated or overmatched. He once cautioned against a premature war with France: “Anyone who’s looked into the glazed eyes of a soldier dying on the battlefield will think hard before starting a war.”
The prudent fear of war goes beyond just an awareness of the severity of war’s violence. It is a consciousness of the volatility of armed conflict, its defiance of control, the difficulty of making mass violence work as a policy instrument, and the ease with which it can turn upon its makers. The American modern realist Stephen Walt warns “Going to war unleashes a vast array of complicated and unpredictable elements that cause most wars to last longer, and cost more, than [leaders] expect.”
Perverse results and hard surprises also informed the vision of the Prussian general and strategist Carl von Clausewitz, especially later in his career when he was chastened by witnessing the many brutal twists of the Napoleonic wars. The nautical metaphor served Clausewitz as darkness served Thucydides. “Every war is rich in particular facts,” he wrote. “Each is an unexplored sea, full of rocks, which the general may have a suspicion of, but which he has never seen with his eye, and around which, moreover, he must steer in the night.”
The elder Clausewitz, in his revisions to On War, stressed the necessity and difficulty of taming conflict to make it serve policy and the challenge of aligning political goals with violence. Would Prussia in 1806, he asked, “have risked war with France with 100,000 men, if she had suspected that the first shot would set off a mine that was to blow her to the skies?”
It would be wrong to portray Clausewitz as an early chaos theorist. He stressed that war was hard to control, but did not advise practitioners to give up on planning. Rather, he emphasised the need for sound judgement in understanding what force could achieve and recommended planning with this in mind. Commanders should anticipate war’s dynamism, leaving room to exploit opportunities. It needed true military genius. A tough ask, yes, but mindful of danger.
In fearing war, realists run against those who look down upon that fear as a suspect, regressive impulse. To speak of “the politics of fear” is to condemn it. President Franklin Roosevelt famously said, “The only thing we have to fear is fear itself.” It is an overrated sentiment. In wartime, FDR made strategy with dangers firmly in mind: in his careful management and manipulation of public opinion, in his efforts to concentrate power and prioritise America’s campaign by choosing “Germany First”, and in his combination of delay, compromise and ambiguity with which he held together a difficult coalition with Britain and the Soviet Union. In truth, there is much to fear. Those fears are part of our impulse to survive.
It was the nuclear revolution that made the problem of war’s wildness all the more intense. Nuclear weapons made the resort to major war vastly more unattractive, because nuclear weapons, unlike other weapons, were almost impossible to stop or shoot down, and could instantly inflict unacceptable (and unpreventable) harm on what an adversary most valued, such as a capital city. Yet the condition of mutual deterrence, of nuclear stalemate around mutually assured destruction, also raised fresh fears.
Even if nuclear weapons made all-out major war between dominant powers suicidal, deterrence was never automatic. Deterrence worked because all sides chose to restrain themselves. A nuclear superpower could forget restraint and be overconfident that its arsenal would deter the adversary, pushing forward adventurously and provoking inadvertent escalation. Nuclear deterrence depends on sustaining fear.
The Cold War made this problem a nightmare. During the Cuban Missile Crisis, President John F. Kennedy resisted the advice of his hawkish counsellors who urged him to go beyond a blockade of Soviet ships and launch attacks on the missile sites in Cuba. We now know that Soviet commanders in Cuba were authorised to use nuclear missiles to attack the US naval base at Guantanamo. Kennedy’s advisers feared weakness and underreaction, and not the attacks they recommended. Kennedy and Nikita Krushchev’s fears saved the world.
A similar awareness moved the political theorist Hans Morgenthau during the Vietnam War. Mindful that war is a political act of clashing wills not easily mastered by social-scientific knowledge, Morgenthau warned against those who were over-certain that intensive bombardment by the United States would break North Vietnam’s will, or that technically measured counterinsurgency would win over the Vietnamese. Later, a consciousness of war’s volatility informed other realists’ arguments against the invasion of Iraq in 2003. That adventure, they warned, “could spread instability in the Middle East”, draw the US into a hard, costly campaign after it toppled Saddam Hussein, and make terrorism worse. Eliot Cohen by contrast argued, “Iraq can’t resist us.” Without fear, hubris rises.
War is full of surprises, especially when protracted, and tends towards intensification. It entails the collision of many moving, unstable parts. Uncertainty and lack of information, or information overload, are reasons we have wars at all, since the decision to draw swords flows from prior disagreement over relative strength. Once war begins, all decision-makers can achieve is an approximation of control. In the words of Tarak Barkawi, a clash in arms is an act of radical contingency that mocks attempts at systematic, secure knowledge. Unexpected resistance and surprising capitulation are part of the spectrum.
War does not take place in well-lit, neat drawing rooms, with generals shuffling pieces across the board, but in places where weather, climate and topography exert their effects, overtly or insidiously. Fighting swings like a pendulum, moving between geographies and from offence to defence and back. Ukraine has had a difficult time transitioning from mobile fighting over a fluid front, to fighting an entrenched Russia in a more attritional grind.
Adversaries work to deceive one another. Since participants have much invested in the fight, they are prone to corrupt analysis with wishfulness. How many times over two decades did we hear that NATO was approaching the decisive period of the war in Afghanistan, with victory just around the corner?
The dynamism of war is again on display in Ukraine. The conflict has confounded many forecasts of defence experts, turn by unexpected turn. Despite specialists’ expectations, Vladimir Putin invaded. Against predictions, Ukraine put up strong resistance, initially hurling Russia back. Ukraine’s defeat of Russia’s naval forces in the Black Sea, freeing up its shipping supply lines without a surface fleet of its own, is stunning.
Yet, Ukraine’s subsequent campaign to evict the aggressor has run up against fortified defences and a dug-in, determined occupier. Contrary to predictions Moscow would soon fall into economic collapse and isolation, Russia has traded with hedging neutral states and revived its defence industrial base. Where pre-war futurologists forecast an era of ambiguous, lighter, techno-centric “hybrid” clashes in the shadows, here was war of iron and mass, out in the open and undisguised.
These trend lines have not yet led to Kyiv’s capitulation or fall. For its part, Russia is still in the field and its despotic regime is intact. Any serious Russian domestic uprising is the dog that has not (yet) barked. Whether American arms and assistance will continue to flow in, supplying the lion’s share of Ukraine’s arsenal, remains uncertain. Now that Donald Trump is president, it is not clear whether Washington will cut Kyiv off, given Trump’s conflicting impulses. As things stand, a drawn-out, grinding stalemate leading to tacit compromise seems the likeliest future. But it is surely time to give cocksure prophecies a rest.
Though realists caution that the risks of more intense escalation in Ukraine are real, they aren’t united in their preferred policies. Some advocate early preparation to negotiate a settlement, others advocate arming and aiding within strict limits. But in common, they emphasise that the wisest course is to steer between the deficiency of doing nothing and the recklessness of assuming a passive opponent.
Realists could be overstating the dangers, of course. Against dire warnings, major war beyond Ukraine has not yet erupted, and despite its rhetoric, Moscow has neither attacked NATO nor used nuclear weapons. So far, nightmare scenarios have proven premature. But we cannot know. In future, a more desperate adversary like Russia could be tempted to reach for its ultimate weapon to offset a defeat that looks threatening to the regime or country. We should take that possibility seriously.
The recourse in extremis to battlefield nuclear weapons, in order to shock oncoming adversaries into backing off, was part of NATO doctrine in the later years of the Cold War. The mutual survival of the West and the Soviet Union through the Cold War depended on alertness to such dangers, fear and the reciprocal restraint that deterrence requires.
Like the dark sea that Clausewitz warned of, war in realist accounts has a turbulent, opaque quality which demands scepticism and wariness about excessive certainty. Fear, often a derided impulse, must have its place. Recall Thucydides’s portrayal of the Athenian leader Pericles, who both reassured fellow citizens when they fell into a blind panic and, when hubris arose, “brought them back to a sense of their dangers”. May we keep ours. There is no useful place for “be not afraid” in the nuclear age.
