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NATO Intervention in Ukraine Won’t Spark World War III

A Western aversion to casualties and fears of Russian nuclear use are impeding NATO intervention against a vastly inferior opponent.

By , a policy advisor and researcher based in London.
Russian Topol-M intercontinental ballistic missiles drive through Red Square during the nation's Victory Day parade in Moscow on May 9, 2009 in commemoration of the end of World War II.
Russian Topol-M intercontinental ballistic missiles drive through Red Square during the nation's Victory Day parade in Moscow on May 9, 2009 in commemoration of the end of World War II.
Russian Topol-M intercontinental ballistic missiles drive through Red Square during the nation's Victory Day parade in Moscow on May 9, 2009 in commemoration of the end of World War II. NATALIA KOLESNIKOVA/AFP via Getty Images

Liberal democracies have war fatigue. It has been demonstrated by disengagement and withdrawal from conflicts (like in Afghanistan) and limited interventions (like in Syria, Libya, and Yemen), where Western forces reduced dependence on ground forces and concentrated on airstrikes and assistance to other fighting forces, such as the Saudis in Yemen and rebels in Syria. Russia’s annexation of Crimea in 2014 passed with few consequences for Russia, and as Russia prepared to invade the rest of Ukraine on Feb. 24, it was clear that Western nations would stick to a policy of nonengagement.

Sanctions against Russia have been severe, and Ukrainian forces have been receiving weapons, equipment, and valuable intelligence from Western nations, which have allowed them to deploy unexpected force against Russian troops—fiercely contesting their invasion and causing thousands of casualties, loss of tanks, and other armored vehicles, rocket launchers, aircraft, and ships. Diplomatic efforts to keep Russia isolated have also been crucial.

However, Russia’s indiscriminate attacks against Ukrainian civilians—including bombing hospitals and schools as well as the use of horrific weapons, such as cluster bombs and white phosphorus—should drive the West to reevaluate its war engagement policy and take a more active role by implementing a no-fly zone or securing evacuation corridors—perhaps even actively fighting Russian forces.

Liberal democracies have war fatigue. It has been demonstrated by disengagement and withdrawal from conflicts (like in Afghanistan) and limited interventions (like in Syria, Libya, and Yemen), where Western forces reduced dependence on ground forces and concentrated on airstrikes and assistance to other fighting forces, such as the Saudis in Yemen and rebels in Syria. Russia’s annexation of Crimea in 2014 passed with few consequences for Russia, and as Russia prepared to invade the rest of Ukraine on Feb. 24, it was clear that Western nations would stick to a policy of nonengagement.

Sanctions against Russia have been severe, and Ukrainian forces have been receiving weapons, equipment, and valuable intelligence from Western nations, which have allowed them to deploy unexpected force against Russian troops—fiercely contesting their invasion and causing thousands of casualties, loss of tanks, and other armored vehicles, rocket launchers, aircraft, and ships. Diplomatic efforts to keep Russia isolated have also been crucial.

However, Russia’s indiscriminate attacks against Ukrainian civilians—including bombing hospitals and schools as well as the use of horrific weapons, such as cluster bombs and white phosphorus—should drive the West to reevaluate its war engagement policy and take a more active role by implementing a no-fly zone or securing evacuation corridors—perhaps even actively fighting Russian forces.

The main concern is any such escalation could lead to World War III. There are two reasons that this is unlikely. The first is that Russia’s military capabilities are poor relative to those of Western armies. Their forces are not sufficiently trained; their equipment and weapons are dated and inferior; they experience major logistical, operational, and tactical difficulties; and their soldiers have low morale.

The expectation that Moscow could escalate the war into other theaters in an effective way, especially by conventional means, is unrealistic.

Damaging economic sanctions also mean that Russia may not be able to fund a wider war. The expectation that Moscow will be able to escalate the war into other theaters in an effective way, especially by conventional means, is unrealistic. It is possible that if the Russian military continues to struggle, Russian President Vladimir Putin will deploy chemical or even nuclear weapons to increase gains and deter the West from interfering—but that is unlikely.

The second is that Russia has become isolated. To fight a world war, Russia needs powerful allies, which it does not have. Its strongest ally, China, has largely remained on the sidelines since the war started. It abstained from voting against the U.N. resolution demanding that Russia ends its offensive, and it is worried about secondary sanctions if it aids Russia. The only countries besides Russia that voted to reject the resolution were Belarus, North Korea, Eritrea, and Syria—hardly a winning alliance. Both world wars saw blocks of powerful allies fight one another. Currently, such a bloc does not exist on Russia’s side.

These factors mean that there is not a high risk of substantial escalation into total global war. This should be enough to convince Western nations to change their engagement policy and help Ukraine win the war by repulsing an opponent that is considerably inferior militarily to their own forces. It is unlikely to happen for two main reasons: fear of Russian nukes and the West’s aversion to casualties.


The most widely discussed reason is the concern that Russia will use nuclear weapons if NATO intervenes militarily. Putin has reasserted Russia’s right to use nuclear weapons in Ukraine, making this a legitimate concern. However, it is more likely that nuclear deterrence—albeit different to Cold War deterrence—will hold. Russia’s deployment of nuclear weapons, either against Ukraine or against a NATO member state, could incur devastating consequences for Russia.

As then-U.S. Defense Secretary James Mattis said in 2018, dismissing the notion that tactical nuclear weapons are somehow a lesser threat, “Any nuclear weapon used … is a strategic game-changer.” Therefore, if NATO retaliates with a powerful response, either nuclear or conventional, it may target strategic Russian military positions and perhaps even sites of political power, aiming at wiping out Russian military capabilities and targeting those in positions of authority—a move that could threaten Putin’s leadership. A NATO retaliation should therefore be considered a major threat to Putin, especially because rivals include numerous nations with considerable nuclear capabilities, such as the United States, United Kingdom, and France.

Sensitivity to casualties—specifically deaths among troops—has become a major element affecting liberal democracies’ war preparedness, use of force, and decision-making.

In addition, at the heart of this conflict stands national identity. Putin has little motivation to devastate a county that he wishes to annex and has not knowingly made any preparations for using nuclear weapons. Fear of the bomb accounts for one reason behind the West’s decision to leave Ukraine to fight on its own.

Another consideration is fundamental to the West: casualty sensitivity.

Sensitivity to casualties—specifically deaths among troops—has become a major element affecting liberal democracies’ war preparedness, use of force, and decision-making regarding participation in wars.

The trauma of Britain’s so-called lost generation followed the loss of 750,000 troops in World War I. It overwhelmed the public and affected interwar foreign policy and military preparedness in a misguided attempt to avoid another war. The same happened in other liberal democracies scarred by the war, such as France, whereas countries with shallower liberal and democratic traditions—such as Germany, which suffered heavier losses than France and Britain—consequently gravitated toward fascism and reverted to militarism.

Conflict behavior and public attitudes toward wars have undergone deep changes during the 20th and 21st centuries as a result of extensive liberalization and democratization processes. Liberal concepts of individualism, personal freedoms, a reduction in internal violence, and a comfortable lifestyle that includes longer life expectancy brought about changes in attitudes about war—primarily, that it is an undesirable way to resolve conflicts. Rejecting the violence and suffering that comes with it has made it difficult for leaders of liberal democracies to justify to the public participation in wars, especially wars of choice, in which the nation is not under direct threat.

The United States’ interventions in Vietnam, Lebanon, Somalia, and Iraq, for example, were shaped by the casualties incurred. The 1983 bombing of the Marine Corps barracks in Lebanon that killed 241 U.S. service members and the 1993 Battle of Mogadishu, where 18 U.S. soldiers died, provoked powerful reactions against the missions, bringing them to an abrupt end despite them initially enjoying wide public support.

A similar reaction came after the Tet Offensive in Vietnam in January 1968, which resulted in 1,500 American fatalities. It was a watershed moment that changed the debate about the war and led to the shelving of plans for escalation. Support for the second war in Iraq also fell dramatically as deaths mounted, causing the American public to question the necessity of the war or its conduct and chances of success.

Israel’s use of force against Hezbollah in Lebanon has been heavily influenced by casualty aversion. This included an overreliance on air power in an attempt to limit fatalities among ground forces during the 2006 Lebanon War at the price of undermining military effectiveness. Then-Israeli Chief of Staff Lt. Gen. Dan Halutz famously commented: “We didn’t send ground troops into Lebanon because the public couldn’t stomach any more deaths.”

Israel’s withdrawal from southern Lebanon, where forces had been deployed between 1985 and 2000, was also heavily influenced by the public’s dissatisfaction with the casualties incurred, particularly after several costly incidents during the 1990s undermined support for a continued military presence and enhanced criticism of the government.

Nondemocracies and guerrilla and terrorist organizations do not exhibit the West’s aversion to casualties.

Nondemocracies and guerrilla and terrorist organizations do not exhibit such an aversion to casualties. During the Iran-Iraq War, both sides callously scarified children by using them as human minesweepers and shields. Similarly, both the Viet Cong in Vietnam and Hezbollah in Lebanon showed considerable willingness to sacrifice lives despite suffering more losses than their liberal enemies. Then-Egyptian President Anwar Sadat famously said, “Egypt would sacrifice a million Egyptian soldiers” during the October 1973 war against Israel despite not facing an existential threat or serious strategic concerns.

There has been little evidence to suggest there is heightened sensitivity to losses among troops in Russia, a nation with a history of mass deaths in both the world wars, its own civil war, and from the brutal suppression and killing of its own people. The continued use of force in Ukraine, which has resulted in as many as 15,000 Russian military deaths so far according to the Washington Post, indicates that casualties are of no concern to Russia’s top brass. This stands in contrast to Ukraine, which accepts its causalities because it is fighting an existential war for independence and national survival.

Casualty sensitivity has been one of the factors shaping democracies’ behavior, with Western politicians preferring to avoid direct engagement in wars or to limit the use of ground forces, even at the price of compromising objectives and deterrence. It is one of the reasons that a policy of nonengagement was adopted, without question or hesitation, regarding Ukraine, long before Putin raised the alert status of Russia’s nuclear arsenal.

Fear of casualties among soldiers meant that a policy of nonengagement has existed prior to Russia’s invasion—and therefore separately to a concern about escalating into a broader war. This has been understood by Putin, who bet—correctly—that Western nations will not take an active role in the war by using direct force against Russian troops, not only out of fear of escalation but as a result of a preexisting doctrine that seeks to minimize casualties. Had the West exhibited less casualty aversion, this could have acted as a greater deterrent against Russian aggression.


For the war in Ukraine, unlike the risk of escalation and use of nuclear weapons, the risk of incurring casualties is high. Considering how formative aversion to casualties has been, committing troops to fight Russia will require liberal democracies to undergo a major paradigm shift.

But there are ways to mitigate the effect of casualty sensitivity on public opinion. Adjusting the public’s expectations regarding the length of the war and the casualties that will result as well as displaying internal political unity could help. Employing force that relies primarily on air power, which limits casualties, can be used; during Israel’s 2006 war in Lebanon and other wars, this has proved to have only limited effectiveness. However, if done in collaboration with Ukrainian ground forces, this could have better chances of success.

This war brought a shift in attitudes toward wars in Europe. The Germans, famously pacifist since 1945, have undergone the largest shift and now support military aid to Ukraine and a considerable increase in funds to rebuild Germany’s military power. But a bigger shift is needed considering Russia’s aggression.

Russia is no stranger to targeting civilians, as it has done in the carpet-bombing of Grozny in Chechnya, in 1994 to 1995 and 1999 to 2000. It is doing this again now. It is time for the West to stop being afraid of limited threats that are not likely to materialize and to use its military superiority to help Ukraine defend its independence.

Intervention will not turn this local conflict into World War III. It runs the risk of causing a tactical nuclear attack on Ukraine, but this risk is limited given what any retaliation could mean for Russia. The West must therefore decide how long it will refrain from engagement and allow Russia to sow devastation in pursuing expansionist ambitions for fear of casualties or the bomb.

Limor Simhony is a policy advisor and researcher based in London. She was previously the director of counterextremism at the political consultancy firm TRD Policy and a research fellow at the Institute for National Security Studies. She holds a doctorate from the Department of War Studies at King’s College London. Twitter: @limorsimhony

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