Foreign Affairs

by William H. McRaven

    The war in Iran is far from the first time that U.S. policymakers have failed to appreciate the limits of American power. But the Trump administration’s use of military force against the Islamic Republic since February 28 offers a particularly glaring example of a mistake that has often characterized American strategy in recent decades. The war was launched without a clear rationale and with a constantly shifting set of objectives—from changing Tehran’s regime and squelching its nuclear ambitions to, more recently, reopening the Strait of Hormuz, which wasn’t closed until the war started. The results, not surprisingly, have been bad both for U.S. interests and for the Middle East.

    Still, to focus only on the blunders in Iran is to miss a deeper problem in U.S. foreign policy—one that preceded and will outlast Donald Trump’s presidency. Although the particular missteps in Iran may stem from the shortcomings of this president and the team around him, the overestimation of the potential of military force has been a growing feature of American strategy since at least the end of World War II. A tendency to wish away the limits of power accounted for some of the greatest mistakes of U.S. statecraft during the Cold War, with Vietnam the clearest and most consequential example. Yet despite an apparent commitment to internalizing the lessons of that overreach, this American delusion—our excessive faith in the capacity of military power to achieve victory and thereby fundamentally political ends—has gotten worse rather than better, especially in the past quarter century.

    And unfortunately, there is good reason to worry that the delusion will deepen in the years ahead. Presidential power is becoming increasingly personalized as the constraints on it continue to erode. The politicization of the military (along with the diplomatic corps and intelligence communities) is making it less likely that policymakers will receive the best advice, including frank warnings about risks and costs. And the rise of artificial intelligence and new weapons technologies reinforces a sense of complete battlefield awareness and mastery, feeding superpower hubris. The risk of overreach has never been higher, at a time when the damage from overreach is becoming more difficult to repair.

• WIN EVERY BATTLE

    In April 1975, Colonel Harry Summers, a member of the U.S. delegation dealing with postwar issues in Vietnam, was meeting in Hanoi with a North Vietnamese counterpart, Colonel Tu. “You know, you never defeated us on the battlefield,” Summers observed. To which Tu replied, “That may be so, but it is also irrelevant.”

    Summers went on to write a seminal book about the war, On Strategy: A Critical Analysis of the Vietnam War. His key takeaway was simple: there are limits to American power that are neglected at immense cost. War is, and always has been, a contest of human will, shaped by heroism and cowardice, fear and elation, chance and uncertainty; no matter how superior a military force, it is not guaranteed strategic victory.

    The book became required reading for many military officers, including me. I had joined the Naval ROTC unit at the University of Texas two years before the encounter between Summers and Tu. The draft had just ended, and the fall of Saigon was still to come, but discussion of Vietnam consumed our ranks. As I studied the American failure, I came to see that a great strength had become a fatal liability: our fundamental faith that we, the United States of America, had to win and thus would. We had won World War I, we had won World War II, and we had at least fought to a draw, holding off the North Koreans and Chinese, in Korea. And somehow, at all costs, we would win in Vietnam.

    To believe you can win is important. It inspires troops and keeps the public engaged. But when the commitment to winning is not coupled with sound policy judgment, when the principles of war are disregarded in the false belief that technology or firepower can overcome the inherent frictions of combat, when tactical successes are viewed as a guaranteed path to a strategic win, when the cost in blood and treasure rises inexorably while any claim to righteousness collapses, it is essential to reassess. In Vietnam, the answer to mounting losses was simply “more”—more troops, more bombs, more money. To lose the fight was seen as anathema to all we stood for; we would keep fighting in spite of the increasingly evident limits to our power. When the end finally came with the rushed U.S. withdrawal from Saigon in 1975, many military and political leaders could still not understand how the United States had won nearly every skirmish, battle, and fight but lost the war.

    The damage from overreach is becoming more difficult to repair.

    The military I entered in 1977 was struggling in the aftermath of Vietnam. The “peace dividend” meant a dramatic drawdown in manpower and money. Readiness was at an all-time low across the services—army enlistment had fallen by 60,000 and the number of navy ships from around 650 to barely more than 500. Meanwhile, the transition to an all-volunteer military had proved challenging: drug abuse and racial tensions were high, morale among senior leaders and young troops alike was low, and new recruits lacked basic skills.

    When President Ronald Reagan took office in 1981, he began the largest peacetime expansion of the U.S. military since the Korean War. Over the course of eight years, he increased defense spending by 35 percent. There was a slew of major procurements: the M-1 Abrams tank, the Bradley Fighting Vehicle, the Apache and Black Hawk helicopters, the F-15 and F-16 fighters, the B-1 bomber, the E-3 Sentry. The navy built back toward 600 ships, including 15 aircraft carriers, 100 attack submarines, and cruisers and destroyers equipped with the revolutionary Aegis Combat System. For troops, pay rose, recruiting goals were met, and standards were restored. Just as important, Congress passed the Goldwater-Nichols Act in 1986. It fundamentally changed the military by strengthening the role of the chairman of the Joint Chiefs of Staff, establishing the regional combatant commanders as the warfighters, ensuring joint force integration, improving joint planning and procurement, and leading to the establishment of the U.S. Special Operations Command. By 1990, the military I entered in the 1970s had been transformed. Our troops were well trained, well equipped, highly motivated, and, most important, well led.

    In July 1990, I left San Diego on a routine six-month deployment to the western Pacific. I was a SEAL task unit commander assigned to Amphibious Squadron Five and the 13th Marine Expeditionary Unit. Little did I know that this reinvigorated military and our civilian leaders were about to be tested, raising the question of whether the United States had learned anything from Vietnam and the other failed missions of the recent past.

• IS IT WORTH IT

    On August 2, 1990, Iraqi President Saddam Hussein ordered the Iraqi army into Kuwait. Within hours of the invasion, the National Security Council convened and options for U.S. action were presented to the president. “This is the first test of the postwar system—as the bipolar world is relaxed, it permits this,” Deputy Secretary of State Lawrence Eagleburger emphasized. “If [Saddam] succeeds, others may try the same.”

    Fortunately, American leadership had never been stronger or more experienced—and in wartime especially, leadership matters. President George H. W. Bush was a young navy pilot when he was shot down near Iwo Jima and eventually rescued by an American submarine. Bush understood war. Later in life, he had served as U.S. ambassador to the United Nations, de facto ambassador to China, director of the Central Intelligence Agency, and vice president. No president in American history had come into office with more national security experience. Nevertheless, Bush surrounded himself with some of the most remarkable diplomats, military officers, intelligence professionals, and strategic thinkers of their time: Brent Scowcroft, the national security adviser; Secretary of State James Baker; Secretary of Defense Dick Cheney; Colin Powell, chairman of the Joint Chiefs of Staff; and many more.

    U.S. Central Command, which would spearhead the military effort against Saddam, was led by General Norman Schwarzkopf. Schwarzkopf was a Vietnam veteran who had been awarded three Silver Stars for heroism and two Purple Hearts for combat injuries. Upon his return from Vietnam, Schwarzkopf had reflected: “Nobody is more antiwar than an intelligent person who’s been to war. . . . And when they get ready to send me again, I’m going to have to stop and ask myself, ‘Is it worth it ’ That’s a very dangerous place for the nation to be when your own army is going to stop and question.”

    Grappling honestly with that question—Is it worth it —is the imperative of good leadership. Bush carefully weighed the costs and risks associated with confronting Saddam and decided the war was worth it. Together, the United States’ political and military leaders developed a strategy with clear goals and objectives and built both popular and international support for the operations to come. It would prove to be the finest application of political and military power in recent American history—and its success is thus worth lingering on.

    The success of the Gulf War rested on several fundamental principles that were at the heart of American strategy. First, that the United States should begin by taking the moral high ground. The high ground implies that you hold a dominant position when facing an enemy. The moral high ground shows that the fight is worth it. With it, leaders can inspire troops, galvanize publics, and rally allies.

    Immediately after Saddam’s invasion, Bush ordered the deployment of military forces into the region and worked with Saudi Arabia to establish a footprint in the kingdom in the event military action was necessary. Bush was still hoping to avoid a conflict, but he saw a similarity “between the Persian Gulf and the situation in the Rhineland in the 1930s, when Hitler simply defied the Treaty of Versailles and marched in.” Yet he knew that he had to convince the international community and the American people that any actions he might take would be moral, legitimate, and in the interests of the United States and its allies.

    Bush and his team engaged in a full-court diplomatic effort to build support from Arab states in the region, from European allies, and from Moscow and Beijing. Although skeptical of the United Nations, Bush nonetheless sought a variety of UN resolutions that condemned Iraq’s invasion, imposed sweeping economic sanctions, and authorized the use of force if necessary. Simultaneously, he built the case with the American people, a large majority of whom ultimately approved of his handling of the crisis. And although Bush believed he had the authority as commander in chief to commit military forces without congressional approval, he sought and received Capitol Hill’s support.

    Second, Bush and his administration recognized the value of building an international coalition, even if the United States had the firepower to go it alone in strictly military terms. This was partly about legitimacy, partly about the chance to send a message. Saddam’s invasion presented an opportunity to shape what some in the administration thought of as a “new world order,” one in which aggression would be met with collective action; major powers would come together despite their ideological differences; and the United Nations and international law would play a critical role rather than be ignored. Bush leveraged the strong personal relationships he had developed over his long career in public service, gaining the support of everyone from Germany’s Chancellor Helmut Kohl and France’s President François Mitterrand, to Saudi Arabia’s King Fahd and Egypt’s President Hosni Mubarak, to Soviet leader Mikhail Gorbachev. As secretary of state, Baker also embarked on a campaign of shuttle diplomacy that took him across the globe, adding to the coalition.

    In the end, the United States did not simply get the support of the international community. Much of the costs of the conflict were borne by others. The allied force ultimately assembled—750,000 troops from 36 countries, including 540,000 Americans—was the largest since World War II. It included, critically, an Arab coalition with forces from Saudi Arabia, Kuwait, Egypt, Syria, Qatar, the United Arab Emirates, Oman, and Bahrain. The coalition was challenging to manage; British Prime Minister Winston Churchill once quipped that “there is only one thing worse than fighting with allies, and that is fighting without them.” But Bush understood that international support brought operational legitimacy and regional stability. It sent a message to Saddam and to the world.

    Third, Bush and his advisers were intent on establishing clear goals and objectives, with political and military dimensions aligned. Politically, the purpose was to uphold international law and restore peace in the region. The military objectives supported those political objectives. The coalition would drive Iraqi forces out of Kuwait. But in doing so, it would attempt to minimize friendly casualties, maintain the alliance, and limit the duration of the war. U.S. leaders were clear from the beginning: there would be no push to Baghdad or protracted engagement with the Iraqi army.

    To defeat the enemy, you must stand on the ground he holds dear and own it.

    Yet even with these limited objectives, neither civilian nor military leaders were under the illusion that success would be easy or cost-free. Driving out a determined enemy that owns the terrain requires overwhelming firepower and a willingness to commit to ground operations. As Carl von Clausewitz stressed in On War, the defense is stronger than the offense, since the defense has only to preserve and protect, while the offense must impose its will on the enemy. He argues that the only way to overcome the inherent strength of the defense is through overwhelming firepower. The Iraqis were prepared to defend the ground they had taken in Kuwait; they owned the terrain, the geography was in their favor, and they had an experienced fighting force after eight years in combat against the Iranians. But Cheney, Powell, and Schwarzkopf understood the principles of war. They had a clearly defined objective. They massed U.S. firepower in the most important areas, accepted risk in less important ones, and were prepared to maneuver against the enemy. And they were committed to leaving when the objectives were reached, not allowing the war to go on too long.

    To accomplish these goals meant putting troops on the ground—a lot of troops. U.S. military and civilian leaders understood that defeating the Iraqis would take more than just airpower. Early on, Cheney observed, “The history of air campaigns suggests they are not terribly successful.” Powell agreed: “To further deter Iraqi action with Saudi Arabia would require U.S. forces on the ground. . . . It would mean a major confrontation. Most U.S. forces would be committed to sustain not just for one or two days.”

    If I have learned one important lesson in over four decades of military service, it’s that to defeat the enemy, you must stand on the ground he holds dear and own it. It is why Alexander invaded Persia, William the Conqueror crossed the channel to England, Genghis Khan rode into China, Sherman marched to Atlanta, the Allies landed at Normandy, and the United States rolled into Kuwait. (It is why today the Israelis are in Gaza and Lebanon and why the Russians will never be victorious until they hold Kyiv.) But as Cheney cautioned, “We should start this only if we are prepared to see it through. . . . The problem is the American people might have a short tolerance for war.”

    Operation Desert Storm began with air attacks at 2:38 AM Baghdad time on January 17, 1991. After 43 days of air operations and 100 hours of ground operations, Washington’s political and military objectives had been achieved. The Iraqi army was ousted from Kuwait, and most American forces were soon on their way home.

    “We’re doing something decent and we’re doing something good,” Bush wrote in his diary. “Vietnam will soon be behind us.”

• LESSONS UNLEARNED

    Desert Storm was a reset, but not in the way it should have been. It presented an opportunity to internalize lessons about how to use force effectively and about what military power could and could not achieve. Instead, it spurred a wave of triumphalism. When I returned from Desert Storm, where I’d led a special operations task force, the euphoria was palpable: we were winners again. The victory proved intoxicating, drawing us back into the false belief that our power could do almost anything to shape the world to our liking.

    Adding to this euphoria was the technology that had been on display against Iraq. Precision-guided munitions could put a 500-pound bomb on a moving target from 20,000 feet in the air. Tomahawk cruise missiles could be launched from ships and submarines hundreds of miles away. A GPS satellite could guide an infantry battalion across a flat desert at night and get it to exactly the right destination, and the joint surveillance target attack radar system could see the Iraqi army as it maneuvered. Digital command and control systems could provide computerized air-tasking orders, secure satellite communications, and digital planning tools. No military in history had ever commanded the battlespace as precisely as we did during Desert Storm. It made sense to build on this success to spur a revolution in military affairs that would improve the way the United States fought. But the experience also fueled a widespread belief that technology could overcome the inherent frictions, costs, and risk of war.

    In the 1990s, U.S. military missions, in line with the confidence that followed Desert Storm and the hopes of the post–Cold War world, were focused on supporting norms and containing humanitarian harms—some successful (Bosnia and Kosovo), some less so (Somalia). But it was after 9/11 that the failure to learn the right lessons from the Gulf War became especially clear, with a persistent misunderstanding of the limits of American power and what the military could and couldn’t achieve. The war in Afghanistan began with the right intentions but devolved into a protracted fight with shifting goals, misaligned military and political objectives, and a determined Taliban force fighting on its home ground. Even after the special operations mission that killed the al-Qaeda leader Osama bin Laden, the goals and objectives in Afghanistan kept shifting. As always, the strength of the military was our troops: they were courageous, disciplined, technologically savvy. We made mistakes, but there was no lack of fighting spirit or tactical successes. Even public support remained strong throughout most of the war. But we faltered by assuming that the quick victory could extend to the complex task of fighting an insurgency, conducting counterterrorism operations, and building a nation. Lest I appear too righteous in my critique of American strategy, make no mistake: as a combat leader in Afghanistan, I fell into the same trap of believing that more troops, more weapons, and more money could solve some of the most intractable problems. They could not.

    The Iraq war, based on a far shakier case at the outset, also degenerated into a counterinsurgency and counterterrorism mission with insufficient forces, a small coalition, and an evolving timeline. Once again, our troops were everything the American people could have hoped for, but our leaders repeatedly disregarded the fundamental principles of war. Our claim to the moral high ground was based on flawed intelligence, our international support was limited, and our goals shifted from removing Saddam to trying to build a Western-style democracy. We may have entered Iraq and Afghanistan with noble intentions, and perhaps in the long term the seeds of freedom we tried to plant will take root. But so far, minimal gains have come at immense cost to our military and our troops, our home front, and our international legitimacy.

• VIRTUALLY INVINCIBLE

    Yet even these recent experiences—which several key members of the Trump administration witnessed firsthand in their own military service—did little to instill caution when it came to Iran earlier this year. To be clear, the Iranian regime is despicable. It is responsible for the death of hundreds of American troops. It threatens its neighbors, uses proxies to attack our allies, and has killed tens of thousands of its own people.

    Given the fall of the Assad government in Syria, the destruction of Hamas’s power in Gaza, the crippling of Hezbollah in Lebanon, and a weakened supreme leader in Iran itself, it is easy to appreciate the allure of trying to change the Iranian regime. What’s more, coming off the dramatic capture of President Nicolás Maduro in Venezuela, where the U.S. military exercised remarkable speed, lethality, and courage to overcome a very sophisticated defense, it was all too easy for U.S. policymakers to assume once again that the power of our technology and the courage and experience of our soldiers made us virtually invincible. But there is a reason no U.S. president has attempted to change the regime in Iran since 1979, and it has little to do with determination or political will. The challenges of legitimacy, coalition building, and geography; the will of the enemy; and the reality that it would be necessary to put American boots on the ground to achieve such an ambitious end all argued against it.

    From the start of the Iran war, there was no attempt to build international legitimacy. It began on February 28 with a U.S.-Israeli strike. To make matters worse, an early airstrike went awry and hit an Iranian elementary school, resulting in the deaths of 120 students. Mistakes happen in war, but not acknowledging our error added to the sense of illegitimacy and vindictiveness, losing whatever moral high ground we might have had. The Trump administration failed to notify any U.S. allies of the impending strike, most notably neighboring Arab states, which resulted in a lack of regional trust from the outset. Later, when the president sought allied support to open the Strait of Hormuz, he was met with an international cold shoulder. This refusal came as no surprise: Trump had been notoriously caustic with European leaders.

    Never underestimate the enemy’s will to fight.

    There was never a clear understanding of the goals. The administration at first said it wanted regime change. But later Trump told reporters that he never cared about regime change. The administration claimed the urgency of preempting an imminent Iranian nuclear weapon. But when pressed, Trump later dismissed such concerns as inconsequential, since there was little left in Iran but “nuclear dust.” After Iran closed the strait, and reopening it to shipping became the primary focus of both military strategy and diplomacy, Trump told the world that it mattered little since the United States didn’t need the oil. The objectives seemed to change by the day. I have no doubt that American military planners understood the limits of airpower when it came to achieving U.S. aims in Iran; this should have been a signal to the White House that unless the military planned to invade Iran, victory was unlikely.

    Geography was always going to be a limiting factor. In my almost 40 years of military service, much of that time in the Middle East, no general or admiral I ever met talked about Iran without talking about the Strait of Hormuz. It was the Iranians’ weapon of mass destruction, their bulwark against invasion, their ace in the hole no matter the game. Additionally, the Iranian leadership was in the position of the defenders: they only had to preserve and protect themselves to win. And protect they have. At this point, it is highly unlikely the U.S. military will ever stand on the ground they hold dear and call it our own.

    The U.S. war was also limited by the will of the enemy. From 1980 to 1988, Iran and Iraq fought a vicious war claiming the lives of hundreds of thousands of Iranians. It should have been clear from the beginning of this war that the Iranians would fight and fight hard. The zealots in Iran control the narrative, and they are battling for their survival.

• THE LIMITS OF POWER

    Such a grave failure to recognize and appreciate the limits of power is not a new phenomenon in American history, or in military history more broadly. With every revolution in military technology, from mounted cavalry to motorized units, from the single-shot musket to the Gatling gun, from propeller-driven aircraft to jets, leaders desperately want to believe that they can wish away the basic nature of war. As our ability to project power around the globe becomes more formidable, we desperately want to believe that geography is no longer important. As new media allows us to see national outrage among an adversary’s population, we desperately want to believe that we can spur change with little risk or commitment. And as AI speeds up tactical decision-making, we desperately want to believe that the lessons of military experience can be disregarded. These beliefs are illusions.

    More concerning, however, is that there are several structural trends in the United States that suggest the problem will get worse rather than better, no matter how vivid the lessons of the Iran war may seem at the moment. The first is the trend toward more personalistic presidential leadership, in which loyalty to the leader becomes more important than loyalty to institutions. When institutions designed to provide a president with the best military, diplomatic, economic, or intelligence advice are led by loyalists, there is a risk that advice will be shaded, inadvertently or intentionally, to reflect the president’s desires. This is a recipe for disaster. A leader needs the unvarnished truth, the best advice possible, regardless of his or her personal position on the issue. The growing concentration of power in the executive branch has unfolded over several administrations, and despite occasional noise from Congress, there is little sign this will change. Here, too, Trump may be a particularly flagrant example, but he’s unlikely to be the last president susceptible to such temptations and operating with few constraints.

    The dangers of personalistic presidential leadership are severely exacerbated by more politicized leadership in the military. Defense Secretary Pete Hegseth’s ongoing purge of military leadership will undermine the civil-military dynamic for years to come. Trump and Hegseth have forced out senior officers across nearly every service, including the chairman of the Joint Chiefs of Staff, the chief of naval operations, and the army chief of staff. Hegseth has intervened to block career advancement in unprecedented ways, personally removing dozens of officers from promotion lists, often with no explanation (although a disproportionate number seem to have worked for leaders who were viewed as obstacles to Trump’s domestic political goals). While remaining military leaders will largely stay committed to serving honorably and providing their best advice to civilian leaders in the Pentagon and the White House, this purge is bound to have a chilling effect on the willingness and ability of senior officers to give frank counsel, especially when it comes to the costs and limits of what force can achieve.

    And finally, the rapid introduction of new technologies, from AI and unmanned vehicles to robotics, cyber- and space-based systems, will once again make it all too easy to wish away the fundamentals of war. Technology will always be an important factor in how wars are fought, and every military must seek greater lethality, survivability, and situational awareness. But although these capabilities are necessary, they are not sufficient to overcome the basic principles of war. Leaders must understand technology for what it is—an enabler. It can improve the application of military power, but it cannot compensate for misguided policies that draw us into conflict in the first place.

• ALL THE POWER IN THE WORLD

    Today’s U.S. military is the finest, most professional armed force in the history of the world—yes, the history of the world. But that doesn’t mean we can disregard the limits of our power.

    We will be limited by moral uncertainty. If the reasons for a conflict are dubious or worse, it will prove challenging to build a coalition, motivate troops, maintain civilian support, and undermine the will of the enemy. Such failures explain why the Greeks defeated the Persians at Salamis, the English defeated the Spanish at Gravelines, George Washington defeated the British, the Russians defeated the Germans at Stalingrad, the Vietnamese defeated the French and the Americans, and the Ukrainians are defeating the Russians today. Although the moral high ground does not guarantee military victory, it is a foundation on which success rests.

    We will be limited by geography. No matter the advances in technology, geography will always be a critical factor in determining the outcome of any engagement. Every military leader knows that the terrain dictates how the enemy will fight, where he will position his forces, how he will supply his troops. It is the oceans and the rivers that provide natural barriers to an advancing force, and the terrain and the waterways that will limit the ability of the attacking force to maneuver, hold ground, resupply, and project power. The Strait of Hormuz and the Bab el Mandeb Strait present the same challenges as the English Channel, the Rhine, or the Volga.

    We will be limited by the will of the enemy. There is a “sleeping giant” in every population that will rise from its slumber and fight hard, driven by a sense of righteousness, a desire for survival, or both. Invaders, aggressors, and first strikers all elicit a visceral response from the population they seek to mollify. Never underestimate the enemy’s will to fight—a mistake we have made again and again.

    We will be limited by our hesitancy to put troops on the ground. No American wants to lose our young men and women on a foreign battlefield, but sometimes it is necessary to achieve the greater good. During World War I, over two million young doughboys deployed to Europe. During World War II, over five million GIs fought the Nazis and island-hopped to Japan. In both cases, mankind was better for their sacrifice. Of course, if there is any doubt about whether we own the moral high ground, leaders will be hesitant to fully commit. In that hesitation comes defeat.

    We will be limited by time. This is not a uniquely American limitation, but we seem to suffer from it more than most countries. It has been said that the Russians will eat grass before they capitulate. The United States’ reputation is that sooner rather than later, we will tire of the fight and leave. Much of this reputation stems from the reality that our democracy demands public support to sustain a long engagement. Even with a compelling reason to send our young men and women into battle, the cost in blood and treasure can soon outweigh our collective sense of the necessity of the fight.

    Finally, we will be limited by the quality of our leadership, political and military. Without experienced leaders—leaders who understand the need to establish legitimacy, to build coalitions, to have clear and attainable goals, to commit to the task, to limit the duration of the fight to only what is necessary—all the power in the world will be irrelevant.