Over the past decade, the country has moved back to—and appears poised to expand on—that tradition after its exhausting 9/11–induced military ventures that ran such high costs for so few benefits. Moreover, public opinion in the United States is not messianic or in constant search of hegemony or of monsters abroad to destroy.

As part of its move back to a more limited military approach, the United States developed—or further developed—a strategy called “by, with, and through” that was particularly evident in its successful military campaign from 2014 to 2019 against the Islamic State. In this, the United States worked with local forces by providing advice, supplies, and intelligence, and by carrying out air strikes while the locals were expected to take almost all of the casualties. Although this approach is hardly new, it seems to have a future and is currently being applied in the war in Ukraine. It might also be applied to deal with a Chinese invasion of Taiwan.

Impelled by an overwhelming desire to hunt down those who were responsible for the September 11, 2001, terrorist attacks, the United States launched military invasions of Afghanistan and Iraq, where it toppled regimes that had little or nothing to do with 9/11. That task was initially successful but those conflicts soon devolved into extended counterinsurgency (or counteroccupation) wars that resulted in the deaths of more than 100 times as many people as perished on 9/11.

Fear of international terrorism induced those military ventures: without 9/11, it is likely neither would have taken place. The Taliban regime in Afghanistan was blamed for harboring al Qaeda, the perpetrators of the 9/11 attack, and the central argument that impelled—and then perpetuated—the multidecade war was that, if the United States withdrew, al Qaeda would move from its apparently inadequate hideout in Pakistan to again set up shop in Afghanistan to plot and carry out further attacks against the United States. And the Iraq War was substantially justified by the argument that if Saddam Hussein were left in office, then Iraq would develop nuclear weapons and other weapons of mass destruction to dominate the area and provide the weapons to terrorist groups, particularly al Qaeda.¹

There has been a tendency to see these exercises as connected to a coherent, preexisting plan to establish a liberal world order or to apply liberal hegemony.² However, the casualty tolerance of the post–9/11 period was a glaring, extended, and highly consequential aberration. During the quarter century before that, the United States pursued a foreign policy that was far more casualty averse. Over the last decade, the country seems to have resumed—and even expanded upon—that tradition after its exhausting 9/11–induced military ventures that ran such high costs for so few benefits. Moreover, public opinion in the United States is not, and has never been, very messianic about democratization or hegemony, nor has it been in constant search of monsters abroad to destroy.

This paper focuses primarily on substantial military operations as opposed to lesser interventions designed, for example, to rescue Americans besieged in overseas embassies.³ Substantial military operations in the pre–9/11 era were bounded by a desire to limit American casualties. Nonetheless, they still included related elements that often inflicted considerable damage and loss of life to foreigners, such as militarized efforts at regime change, the application of economic sanctions, support for contestants in civil wars, and bombing and drone attacks. Although these elements have been retained in the current era, there are signs that their use will become more attenuated than during the last quarter of the 20th century, between the Vietnam War and 9/11.

In the wake of its withdrawal from the Vietnam War in 1973, the United States fell into something that has been dubbed the “Vietnam syndrome.” There continued to be support for the contest against international communism but not for the tactic of opposing it through armed ground interventions such as Vietnam, where American casualties were suffered in great numbers.

In the late 1970s the United States essentially let its policy of containing the Soviet Union lapse and watched as the Soviets welcomed 10 new countries into its camp: Cambodia, Vietnam, and Laos in 1975; Angola in 1976; Mozambique and Ethiopia in 1977; South Yemen and Afghanistan in 1978; and Grenada and Nicaragua in 1978. All those countries soon became dependent on Moscow economically, politically, and sometimes militarily—particularly Afghanistan, where the Soviets found it necessary in 1979 to intervene with force in order to keep their local allies in power. As it turned out, the Soviets might have been better off being contained, as they eventually came to realize.⁴

Even when American military force was applied during the last quarter of the 20th century, it was done rather sparingly, not in a crusading manner. Its most assertive Cold War actions during that period were a military invasion of the small Caribbean island of Grenada in 1983 and an operation to support the anti-Soviet rebels in Afghanistan after 1979. There were also limited efforts by the Reagan administration to intervene in support of elements in El Salvador and Nicaragua deemed to be anti-Communist, but these were substantially undermined by Congress for fear such ventures might lead to another Vietnam.

Outside the Cold War, the United States bombed Libya for a day in 1986 in retaliation for the Libyan government’s sponsorship of terrorist activities; launched a failed effort in 1980 to rescue US diplomats held hostage in Iran; invaded Panama in 1989 to depose an offending regime; and led an armed international coalition in 1991 of hundreds of thousands of troops to reverse Iraq’s invasion of Kuwait, a venture that restored Kuwait’s illiberal government (and thus was scarcely part of a crusade for democracy). In all these cases, America’s opponents were hardly formidable. For example, although the Iraqi army may have looked impressive on paper in 1991 and seemed to some analysts to potentially be an effective opponent, it lacked strategy, tactics, defenses, leadership, and morale, and it responded to confrontation with the US-led offensive mostly by fleeing or by surrendering.⁵ In addition, the government in Haiti, faced with the prospect of a US invasion, was persuaded to flee in 1994. And throughout the 1990s, economic sanctions and no-fly zones were applied to Iraq with little effect on its policy.

Other military ventures Washington pursued between the Vietnam War and 9/11 were even more limited and were mostly carried out not for hegemonic purposes, but for humanitarian ones—something facilitated by the end of the Cold War.⁶ American troops were sent to Lebanon in 1982 to help police a cease-fire there, but they were abruptly withdrawn when 241 of them were killed in their barracks by a terrorist bomb the next year. In 1992, American soldiers helped stabilize Somalia, which was in the midst of a civil war and an attendant famine. But Washington withdrew its forces after 18 American soldiers were killed in a chaotic firefight. Stung by this experience, the Clinton administration did not act to stop the genocide in nearby Rwanda in 1994.

There were also great concerns about the civil war that erupted in the former Yugoslavia in the early 1990s, but, along with much handwringing, the US military role there involved little more than supplying aid and advice and, toward the end of the conflict, conducting limited bombing missions against Serbian targets in Bosnia. Only after the fighting was over did Washington send in ground troops to perform policing operations. A few years later, the United States, citing humanitarian concerns, led a NATO bombing campaign against Serbia to stop violence against ethnic Albanians in Kosovo, but no American forces ever got close to fighting on the ground.

Overall, this record does not suggest a country that is trying to expand, looking for a fight, crusading for democracy, questing after monsters to destroy, or seeking to act like a hegemon. Indeed, as foreign policy expert Christopher Preble puts it, the efforts often “had an ad hoc quality about them” and they “seemed purely reactive” and not “part of a broader US campaign to shape the world order to suit its interests.”⁷ Moreover, when given a list of foreign-policy goals, the American public has rather consistently ranked the promotion of democracy lower—often much lower—than such goals as combating international terrorism, protecting American jobs, and strengthening the United Nations.⁸

American rhetoric between Vietnam and 9/11 did not match its military tentativeness. President Ronald Reagan grandly insisted that world peace was at stake in the civil war in Lebanon, and President George H. W. Bush opined that his war in the Gulf would “chart the future of the world for the next 100 years.” In addition, Bush (and later President Bill Clinton) declared that a coup in Haiti was an extraordinary threat to the security and economy of the United States.⁹ There were also proclamations about how the United States had a responsibility to protect people in other countries as well as ones declaring the United States to be the “indispensable nation,” suggesting that all others were, well, dispensable.

There also was a great deal of crowing after the Soviet Union’s collapse about how the United States had emerged all-dominant, enjoying a “unipolar moment” in which it was “the unchallenged superpower” at the “center of world power” and had the “assets to be a decisive player in any conflict in whatever part of the world it chose to involve itself.”¹⁰ However, as suggested, such vast proclamation was accompanied by half-vast execution. After the Cold War, the United States soon found itself limping out of Somalia, wringing its hands over Bosnia, and, as an excuse for not intervening, trying to deny that genocide was taking place in Rwanda. And, although it repeatedly contended that it had defeated the world’s fourth-largest army in pushing Iraq out of Kuwait in 1991, that army, when its untrained and hastily assembled reserves are excluded, was more like the 10th-largest, and for the most part it was ready to give up before the first bomb was dropped.¹¹

Thus, in contrast to all the hyperbolic and self-important rhetoric, US policymakers showed a strong aversion to bearing US casualties in support of their visions. Between 1980 and the end of the century, the United States military averaged only about 11 combat deaths per year (Figure 1). If military deaths from terrorist attacks are added in, including the toll from the barracks bombing in Lebanon (which occurred when the victims were off-duty), that number rises to about 29 per year.¹²

The rhetoric mellowed by the time of the presidential election campaign of 2000. No one seems to have opposed George W. Bush’s explicit support in the October 11 debate for a humble foreign policy. Indeed, his Democratic opponent, Vice President Al Gore, deemed the idea to be an “important” one. To a considerable degree, both candidates were in tune with the times.

Any enduring aversion to US casualties temporarily disappeared when al Qaeda attacked the United States on September 11, 2001. After the attacks, Bush proclaimed that the country’s “responsibility to history” was now to “rid the world of evil.”¹³ With this bizarre goal in mind, the United States launched wars in Afghanistan and Iraq, began to hunt down terrorist suspects around the globe as part of its Global War on Terror (GWOT), and established a national security state internally.¹⁴ Although Bush, like most of the Republican Party, had previously ridiculed the concept of nation-building, he now embarked on two such enterprises, each of which lasted decades and, in different ways, failed miserably. As political scientists Monica Toft and Sidita Kushi put it, the attacks were “game-changers” and “ushered in a significant foreign policy reorientation.”¹⁵

Under the impetus of 9/11, it is clear that the public was primarily out to get those who were responsible for the attacks and was willing to suffer extensive casualties in the process. In mid-September 2001, fully 77 percent of Americans favored military action, including the deployment of ground forces, “to retaliate against whoever is responsible for the terrorist attacks, even if that means U.S. armed forces might suffer thousands of casualties.” Moreover, 38 percent anticipated that it would take years to dismantle terrorist networks. And a majority believed that there was a direct connection between Saddam Hussein and 9/11.¹⁶

The militarized reaction to the 9/11 attacks accounts for the overwhelming amount of American casualties suffered in military action over the last 50 years (Figure 1). Political scientist John Mearsheimer, writing in 2014, argues that by then the United States had “been at war for roughly two out of every three years since 1989.” However, this was overwhelmingly due to the 9/11 wars. In the 12 years before that, the United States had waged three wars according to Mearsheimer. Active military participation in these three wars lasted a total of one year, and two of these (the ones in Bosnia and Kosovo) were limited to aerial bombing.¹⁷ Without 9/11, the comparatively casualty-averse military approach of the last quarter of the 20th century would likely have continued. For example, Richard Perle, one of most ardent proponents of war with Iraq in 2003, published an article shortly before 9/11 that, while strongly advocating a policy hostile toward that country’s regime, recommended protecting and assisting resistance movements within Iraq, but not an outright invasion by American troops.¹⁸

Neither of the two post–9/11 wars was necessary. It is unlikely that the insecure Taliban regime in Afghanistan, where al Qaeda had carried out training, needed to be overthrown. The relationship between the Taliban and al Qaeda was often very uncomfortable, and the regime might have been susceptible to international pressure, especially from its rare friends like Saudi Arabia, which had been trying to extradite terror chief Osama bin Laden for years.¹⁹

And Saddam Hussein’s regime in Iraq was unlikely to dominate the Middle East with its ramshackle and unreliable army: he was wary about issuing it ammunition and banned it from entering Baghdad with heavy equipment for fear that it might overthrow his regime.²⁰ Indeed, as analyst Jeffrey Record notes, even if Saddam Hussein “had possessed nuclear weapons, there is no convincing evidence he would have been undeterrable.”²¹ And any connections Saddam Hussein had with terrorist groups were with ones that were attacking Israel at the time, not with al Qaeda.²²

The war in Iraq was not just unnecessary, it was also misguided. As an Army War College study notes, in conducting the Iraq War, US leaders seemed to have believed that other actors would not react. But Iran, a comember with Iraq on Bush’s “axis of evil” hit list, had a huge incentive to make the American occupation of neighboring Iraq as miserable as possible. The study concludes that Iran “appears to be the only victor” of the war.²³ Moreover, terrorists from around the world were attracted to the fray, something that analysts warned about before the US invasion.²⁴

As it became clear just how costly and counterproductive the main conflicts of the GWOT had become, Washington began to shift back to a more cautious military approach.

In the Arab Spring of 2011, it looked for a while like a set of Middle East countries might liberalize or democratize. The military response by the United States in this case resembled the period before 9/11 more than the one after it. It sometimes supported revolutionaries, but from a distance. As it had in Bosnia in the early 1990s, Washington joined a rather large number of other states to assist the rebels in civil wars in Libya and Syria.²⁵ Both efforts failed miserably, however: the rebels lost outright in Syria and those in Libya, after toppling the reigning dictator, fell into civil war among themselves. A more successful military operation was the 2011 military raid into Pakistan that killed bin Laden at no cost in American lives.

A change in US military policy was evident in a major Defense Department statement in January 2012 that stressed that “US forces will no longer be sized to conduct largescale, prolonged stability operations.”²⁶ This suggests that the military and its leaders had concluded that they simply did not know how to successfully execute such missions. In that sense, it expressed a degree of military reticence, even humility. Presumably with this in mind, policymakers worked to reconfigure the wars in Afghanistan and Iraq to reduce the battle death rate of US military forces. In Afghanistan, that rate was more than 400 per year in 2010–2011, but it declined to less than 25 per year later on. The rate in Iraq was around 800 per year between 2004 and 2007, but it declined to less than 70 per year in 2010–2011 and to less than 25 per year thereafter. (All of these rates, however, are much lower than those suffered earlier in the wars in Korea and Vietnam.) In 2014, Washington sent troops back to Iraq to fight the Islamic State (ISIS), but, as will be discussed more fully in the next section, in the years that followed, the United States mostly provided advice and air support while local fighters bore the brunt of combat deaths.²⁷

Both the Obama and Trump administrations moved to reduce US commitments to the “forever wars,” echoing a shift in American public opinion that had come to sour on the conflicts even though they continued to be identified with terrorism.²⁸ As after Vietnam, the public continued to support the strategic goal—in this case, fighting international terrorism—but not the tactic of direct on-the-ground intervention. Indicative of the public’s wariness about military ventures abroad was its response to bipartisan support in Congress in 2013 for the punitive bombing of Syria after the ruling regime of Bashar al-Assad was deemed to have carried out a poison gas attack on civilians. Out of concern that the action would lead to further involvement in the conflict, the public was strongly opposed to using force—as members of Congress of both parties found out when they went home to their districts.²⁹

American participation in the war in Afghanistan declined but lingered, lasting so long not because of a desire to spread democracy or to establish liberal hegemony, but, as noted, because of the appeal of the argument that, should the United States fail there, al Qaeda would return to carry out more 9/11-style attacks.³⁰ Yet despite the utter collapse in 2021 of the Afghan forces that were trained and supplied by the United States, and the consequent victory by the insurgent Taliban, no such al Qaeda strike has occurred. The US public reacted with remarkable equanimity to the debacle. And it might be pointed out that, contrary to earlier expectations, al Qaeda has yet to return to set up shop in Afghanistan. Its leader, Ayman al-Zawahiri, who had been successfully holing up in Pakistan for 20 years, did make a visit to the Afghan capital a year after the Taliban takeover, but safety did not follow him, and he was promptly killed in an American drone strike.

Evidence of an emerging public aversion to the 9/11 wars could be seen at least as early as 2005.³¹ Now, the United States seems to have fully embraced an “Iraq syndrome” or an “Iraq/​Afghanistan syndrome,” and has moved back to a considerable degree of casualty aversion. The American public might still support an air or drone campaign against international terrorists, but there is little appetite for invasion and occupation—and none whatever for crusading.

As part of its move back to a more limited military policy, the United States has developed—or further developed—a strategy called “by, with, and through.” This was particularly evident in its successful military campaign from 2014 to 2019 against ISIS. Under this strategy, the United States worked with local forces by providing advice, supplies, and intelligence, and by carrying out air strikes.³² But the locals were expected to absorb almost all of the casualties. And indeed they did: tens of thousands of people were killed in the five-year war, but only 20 of them were American service personnel.³³

Key to the success of the strategy, then, was the willingness of the locals to fight and die for the cause. This quality is difficult to inspire or fabricate, but it helps greatly if the enemy, as in the case of ISIS, is believed by the locals to present a genocidal or existential threat to them.

By 2014, the United States had spent $20 billion to create defense forces in Iraq.³⁴ However, confused and corruption‐​ridden, those forces simply fell apart when challenged by ISIS fighters in 2014, abandoning territory and weaponry even though the defending forces often greatly outnumbered the challengers.³⁵

But there was soon a remarkable transformation: effective forces in opposition to ISIS emerged among the locals. They came not only from the Iraqi army but also from various militia and paramilitary groups, especially Kurdish ones. They often squabbled, and a central US mission was to get them to coordinate their efforts. But all were in agreement on the need to extinguish ISIS and to risk death in the process.

Although this change was likely bolstered by the American commitment, it was caused not so much by that as by local fears and revulsion at the vicious and genocidal tactics and goals of ISIS, which, as analyst Daniel Byman puts it, had a “genius at making enemies” and could not make common cause even with other Sunni rebel groups.³⁶ A poll conducted in Iraq in January 2016 found that fully 99 percent of Shiites and 95 percent of Sunnis expressed opposition to ISIS.³⁷ People’s spines had become steeled by ISIS’s staged beheadings of hostages, summary executions of prisoners, and rape and enslavement of female captives. For example, in 2014, ISIS massacred some 1,700 unarmed captured Shia military cadets by shooting, beheading, and choking them, triumphantly web‐​casting videos of the event. As one ISIS opponent puts it bluntly in the film City of Ghosts, the conclusion for many was “either we will win, or they will kill us all.”³⁸

In addition, the US strategy against ISIS was aided by the fact that Americans came to believe that the enemy presented a direct threat to the United States. This stemmed from the vicious group’s ultimate idiocy: staging and webcasting beheadings of defenseless American and Western hostages in the late summer and early fall of 2014. Only 17 percent of the American public had advocated sending ground troops to fight ISIS after its successful routs earlier in the year because it seemed to be yet another incomprehensible civil conflict among Iraqi factions. However, the beheadings—tragic and disgusting, but hardly on the order of magnitude of the destruction wreaked on 9/11—boosted support to more than 40 percent, and that number went even higher later. A poll conducted in 2016 asked the 83 percent of its respondents who closely followed news about ISIS whether the group presented “a serious threat to the existence or survival of the US.” Fully 77 percent agreed, more than two‐​thirds of them strongly.³⁹ This might be seen a something of a reversion to casualty acceptance. However, it proved to be temporary, and it was not acted upon.

For all the success of the ISIS campaign, civilian deaths might have been lower if ISIS fighters—many of them disillusioned and fundamentally muddled—had been allowed to flee the fray. Instead, US strategy, particularly as put forward by the Trump administration’s secretary of defense, James Mattis, was focused on “annihilating” ISIS.⁴⁰ As a result, sieges of ISIS forces often did not allow them an escape route. This led to situations such as the one in which an American bomb blew up a building that housed two ISIS snipers, reportedly killing 105 civilians in the process.⁴¹ But sometimes, local commanders did allow for escape routes, and this may have saved many civilian lives.⁴²

The concern was that if ISIS fighters were allowed to escape, they would be free to rejoin the battle elsewhere.⁴³ But this conclusion seems to have been based on an overestimate of their capacities and dedication. In fact, after ISIS’s startlingly easy advances of 2014, in which Iraqi defenders mainly fled, it did not show much dedicated military tenacity.⁴⁴ Some of this was evident even early on.⁴⁵ Thus, the group announced in 2014 that it was “ready to burn 10,000 fighters” in one fight but it abandoned the field after the loss of a few hundred.⁴⁶ In late 2015, it launched three badly coordinated offensives in northern Iraq that included “armored bulldozers,” and all were readily beaten back.⁴⁷ Frontline commanders observed of ISIS that “they don’t fight. They just send car bombs and then run away. Their leaders are begging them to fight, but they answer that it is a lost cause. They refuse to obey and run away.”⁴⁸

Increasingly, ISIS sought to ferret out informants within its ranks, some of whom were alienated by sharp cuts in salaries, and executing them by such methods as dropping them into vats of acid.⁴⁹ In defense, ISIS seems primarily to have relied on planting booby traps, using snipers, and cowering among civilians instead of relying on well‐​organized military operations.⁵⁰ For example, to maintain its human shield, ISIS murdered hundreds of civilians who tried to escape, sometimes hanging the corpses from electrical pylons as a warning.⁵¹

Rather than treating ISIS as desperate fighters hiding behind human shields, as US policy dictated, it might have been better overall to let ISIS escape. Some escapees might have fought again, but many seemed to have been thoroughly disillusioned and may well have been anxious to flee the fractious, murderous, and pathological ISIS society. Fears at the time that foreign fighters would return home to commit terrorist attacks were understandable, and that did happen in Paris in 2015 and in Brussels in 2016.⁵² But there were few, if any, such events later: concerns about returnees proved to be substantially unjustified.⁵³

After the extended, tragically costly, and fundamentally absurd aberrations caused by the overreaction to 9/11, a more limited American military approach appears to be back—and perhaps is even more embraced than in the post-Vietnam decades.

However, it should be pointed out that there is still plenty of spending on the military and on its bases around the world even after its failures in Afghanistan, Iraq, and Libya. Moreover, sanctions seem to have retained their appeal despite little evidence of their effectiveness at changing policy.⁵⁴

But, although the GWOT lingers on, this has now mostly involved the training of local police and military forces and the use of drones; there have been almost no American military casualties in recent years. In fact, casualty aversion may be greater than in the post-Vietnam period. For example, there likely will be little support for extended bombing raids after the failure of the tactic to deliver long term success in Libya.⁵⁵ Indeed, regime-changing military actions such as those launched against Grenada, Panama, and Haiti in the post-Vietnam era scarcely seem to be in the cards: they have been discredited by the failures during the 9/11 period in Iraq, Afghanistan, Libya, and Syria. In addition, intervention in civil wars, after the failed experiences of outsiders in Syria and Yemen, may be fading as a viable strategy even though support for local Ukrainian resistance to a Russian invasion remains relatively high. Toft and Kushi argue that “the United States is increasing its use of force abroad” and “has become addicted to military intervention.”⁵⁶ But that addiction seems now to be in something of remission.

Moreover, as the country limps now from its 9/11–induced failure in Afghanistan, it seems possible that official rhetoric will mellow. Proclamations about America’s superpower, exceptionalism, and indispensable nationhood, seen by many to be arrogant, may subside.⁵⁷ Even notions about the responsibility to protect are losing their sheen, and the same may hold for arguments that some sort of global struggle is going on between democracy and autocracy.

However, since it minimizes US casualties, the strategy of “by, with, and through” will likely continue. Although journalist Michael Gordon contends that the strategy constitutes a “new way of war,” it is not clear that it is all that new: Gordon himself espies elements of it in earlier interventions.⁵⁸ In fact, in many respects, it was fully on view in the American (and European) approach to civil wars in Bosnia and Croatia in the early 1990s. The outside interveners were willing to supply and advise one side in those conflicts and even to apply some focused bombing. But, as noted, US troops were sent to police the situation in 1995 only after the wars had been substantially settled—when the military environment had become “permissive,” as it was put at the time by President Clinton and others. Helpful to the success of the mission was the fact that the opposing Serb forces were substantially incompetent and criminalized.⁵⁹

Something similar could be seen in US strategy during the last years of the Vietnam War. Sapped by declining popular support for the war at home, the US contribution had been reduced to a supporting role by 1971, while the South Vietnamese forces that America had trained were expected to bear the brunt of any ground fighting. In 1972, North Vietnam launched a major offensive, and for a while it looked like South Vietnam’s military would fold. However, some elements did hang on, blunting the offensive. When that was obvious, the United States reentered combat, but mainly with airpower, and the combined effort defeated the offensive. But three years later, when the North Vietnamese launched another offensive, the ill‐​led South Vietnamese military did collapse, and the United States mainly stood back and withdrew its personnel, watching as the North Vietnamese took over and handed the United States the greatest debacle in its foreign policy history. As with America’s later withdrawal from Afghanistan, failure was accepted with remarkable equanimity.⁶⁰

Foreign policy columnist David Ignatius argues that the United States military may well have found a winning combination in its war against ISIS.⁶¹ However, as the Vietnam experience suggests, it needs local forces that are prepared to do the fighting and dying. Indeed, in a broader comparative study, analyst Stephen Biddle and his colleagues conclude that security force assistance works best—and perhaps only—if the locals are convinced that they face a mind-concentratingly existential challenge. Otherwise, their interests are likely to depart considerably from those who are assisting them.⁶²

Nonetheless, Gordon’s contention that this way of war has a future seems to be on solid ground. In interviews, he has suggested that a version of the strategy is currently being applied by the United States and its allies in the war in Ukraine. Following the approach used when the Soviets invaded Afghanistan in 1979, there has been support for aiding locals opposing the invasion, but not for direct intervention by American ground troops.

Although the United States and NATO had done some training and had sent military aid to Ukraine in previous years, they were wary and expected that, if a Russian invasion took place, the Ukrainians might well fold the same way that US-trained forces had in Iraq in 2014, in Afghanistan in 2021, and in South Vietnam in 1975. They were especially concerned about supplying intelligence because Ukraine’s intelligence apparatus was shot through with Russian moles.⁶³

However, once the Ukrainians proved to be dedicated and effective at defending against a threat that they perceived as endangering the existence of their state, the essential element in the “by, with, and through” strategy was established. This was bolstered by outrage at the Russian invasion, outrage that inspired broad popular support in North America and Europe for a costly assistance effort.⁶⁴ Although the war is sometimes advertised as a conflict between democracy and authoritarianism, support for the Ukrainians has been primarily motivated by hostility to international aggression, as it was when authoritarian Iraq invaded authoritarian Kuwait in 1990.⁶⁵

Moreover, outside support for dedicated forces like those in Ukraine may be more readily sustained because the “by, with, and through” strategy does not require that casualties be suffered by the supporters. Mounting US casualties were the essential cause of the decline in popular support for wars such as Vietnam, Iraq, and Afghanistan, not events in the war (which generally proved to have only a short‐​term effect) or the antics of anti‐​war demonstrators.⁶⁶

But if the conflict in Ukraine suggests that this way of war has a future, it is a limited one. As experiences in Vietnam, Iraq, and Afghanistan attest, dedicated local forces cannot readily be fabricated by well‐​meaning outsiders, even after decades of effort and expense.

A degree of military reticence can also perhaps be seen today in the reaction to the rise of China, which many see to be a primary danger. Even alarmists push for little more than rearranging the US military or selling submarines to allies in a potentially quixotic effort to somehow balance against China’s primarily economic rise. Other proposals have even less bite. For example, they advocate working with allies, improving American officials’ understanding of China, calling out China’s repressive policies, countering Beijing’s efforts to potentially control communication networks, and cooperating on common interests such as climate change.⁶⁷ But there isn’t much call for major military operations to counter China.

However, a test might come if China attempts to take over Taiwan by military force. If local forces resist effectively, as happened in Ukraine, it seems rather likely that the “by, with, and through” approach will be applied by the United States in much the same manner as in Ukraine.⁶⁸ If Taiwan’s forces fold, however, experience suggests that outsiders are unlikely to try to rescue them on their own. That is, the US response is more likely to resemble the post-Vietnam and the post-GWOT periods than the aberrant casualty-accepting period after 9/11.

Mueller, John. “A Return to US Casualty Aversion: The 9/11 Wars as Aberrations,” Policy Analysis no. 971, Cato Institute, Washington, DC, April 2, 2024.