President John F. Kennedy and his Secretary of Defense Robert McNamara
In 2003, Errol Morris released The Fog of War, a documentary built around an unusual act of historical reckoning. Robert McNamara, the former secretary of defense who had helped shape American policy in Vietnam, sat before Morris’s camera and attempted to explain what he had learned from a war that had gone so badly wrong.
McNamara had once been the archetype of the modern American technocrat. He believed in statistics, systems, rational analysis and the capacity of intelligent men to solve seemingly intractable problems. Yet Vietnam had forced him to confront the limits of all of them.
By the time Morris interviewed him, McNamara was an old man looking backward. More than 58,000 Americans had died in Vietnam, along with millions of Vietnamese. The war had damaged American political life, devastated Vietnamese society and permanently altered the country’s relationship with its own military power.
McNamara distilled his reflections into eleven lessons.
They were ostensibly lessons about Vietnam. They were really lessons about human beings, power and the dangerous confidence with which governments make decisions about war.
That is why The Fog of War feels newly relevant as Donald Trump’s war with Iran approaches its sixth month.
Iran is not Vietnam. The analogy should not be pushed that far. The conflicts have different origins, different enemies, different technologies and different geopolitical circumstances. But the mistakes that McNamara identified are not uniquely Vietnamese or American. They are recurring errors in the psychology of power.
Put another way, history does not have to repeat itself exactly for human beings to repeat themselves.
The first of McNamara’s lessons was perhaps the simplest and most difficult: empathize with your enemy.
He did not mean that America should excuse its enemies or abandon its interests. He meant that a government cannot make sound strategic decisions if it refuses to understand how its adversary sees the world.
McNamara came to believe that one reason the Cuban Missile Crisis did not become a nuclear war was that American officials tried to understand Nikita Khrushchev’s position. During Vietnam, by contrast, Washington interpreted Vietnamese nationalism largely through the lens of the Cold War. What looked like communist expansion to American policymakers could look very different from Hanoi.
The Iranian government is repressive. Its leaders have pursued policies deeply hostile to American interests. None of that changes the fact that Iranian leaders have their own history, fears, ambitions and conception of national sovereignty.
Understanding an adversary is not appeasement.
It is strategy.
McNamara and a German officer
The danger comes when an enemy is reduced to a caricature. Once that happens, its behavior becomes difficult to interpret except as evidence of its irrationality or evil. Every act of resistance becomes proof that more pressure is necessary.
This leads directly to McNamara’s second lesson: rationality will not save us.
This is one of the most unsettling ideas in the documentary. The problem with war is not necessarily that irrational people make irrational decisions. Rational governments can make catastrophic decisions because they operate from incompatible assumptions about reality.
Washington may believe that overwhelming military pressure will eventually convince Tehran to capitulate. Iranian leaders may believe that capitulation would only invite further demands and ultimately threaten the survival of the regime.
Both sides can act rationally according to their own calculations and still move toward an irrational outcome.
That is the fog.
McNamara’s third lesson, that there is something beyond one’s self, sounds almost philosophical because it is. Nations, like individuals, have a tendency to imagine that their own perspective is the natural center of reality.
American policymakers begin with American interests. Iranian policymakers begin with Iranian interests. Israeli policymakers begin with Israeli security.
Diplomacy begins when those perspectives are allowed to coexist.
A powerful nation has an especially difficult obligation here. The United States possesses an extraordinary military advantage. But power can create its own form of blindness. The stronger a country becomes, the easier it is to mistake the ability to impose costs for the ability to determine outcomes.
McNamara’s fourth lesson was maximize efficiency, an ironic recommendation coming from a man whose career had been built on managerial efficiency.
The deeper point was that efficiency is not effectiveness.
The United States can become extraordinarily efficient at destroying targets without becoming more effective at achieving its political objectives. Modern warfare makes this distinction even more important. Satellites, drones, precision-guided weapons and artificial intelligence allow military planners to identify and strike targets with astonishing accuracy.
But a precisely destroyed target does not answer the question of what comes next.
How many missile sites were destroyed? How many weapons were eliminated? How many sorties were flown?
These are measurable questions.
Whether the war is producing the political outcome Washington wants is much harder to measure.
McNamara and General Westmoreland
The same problem lies behind McNamara’s fifth lesson: proportionality should be a guideline in war.
McNamara spent the latter part of his life wrestling with the moral implications of decisions that he had once approached largely as questions of strategy and national security.
The lesson is not that force is never justified. It is that good intentions do not make violence morally unlimited.
Every military action must be measured against the objective it is intended to accomplish.
That question becomes increasingly difficult to answer as the Iran conflict expands. The war has already disrupted the Strait of Hormuz, one of the world’s most important energy corridors, with consequences extending well beyond the immediate battlefield. Oil prices have risen amid fears that the disruption could continue.
The larger question is not whether the United States possesses the military capacity to inflict additional damage on Iran.
It obviously does.
The question is what that damage is supposed to accomplish.
That brings us to McNamara’s sixth lesson: get the data.
The phrase sounds like a tribute to his technocratic worldview. In retrospect, it is almost a critique of it.
McNamara believed deeply in numbers. But The Fog of War ultimately demonstrates the limits of numerical certainty. A government can know how many missiles were fired, how many targets were destroyed and how many aircraft participated in a campaign without knowing whether the campaign itself is succeeding.
The paradox of modern warfare is that the United States may possess more information about Iran than any government in history while still failing to understand what that information means.
President Lyndon Johnson and McNamara
Data is not wisdom.
McNamara’s seventh lesson is closely related: belief and seeing are both often wrong.
Governments have a remarkable ability to see what they already believe.
The history of the Gulf of Tonkin episode remains instructive because it illustrates how uncertainty can be transformed into certainty and certainty into military action. Once policymakers become convinced that an adversary is preparing to do something, ambiguous intelligence can begin to look like confirmation.
The danger is not simply bad intelligence. It is interpretation.
Intelligence is never merely a collection of facts. It is facts interpreted by human beings who already possess assumptions about what those facts mean.
In wartime, those assumptions can become deadly.
That is why McNamara’s eighth lesson may be the most important of all: be prepared to reexamine your reasoning.
A strategy is not a creed.
If reality contradicts your assumptions, the assumptions have to change.
Yet governments often do the opposite. They establish an objective, apply military pressure, encounter resistance, increase the pressure and then interpret the continuing resistance as evidence that still more pressure is required.
The strategy becomes self-sealing.
Trump has repeatedly presented military pressure as a means of compelling Iran to accept American demands. Yet the conflict has continued, negotiations have faltered and the Strait of Hormuz has become a central point of confrontation. The temporary ceasefire has not produced a durable political settlement.
At some point, persistence becomes something else.
It becomes the refusal to learn.
McNamara’s ninth lesson is perhaps the most morally uncomfortable: in order to do good, you may have to engage in evil.
This is not a pacifist proposition. Governments sometimes face terrible choices. The problem is that the assertion of necessity can become a moral escape hatch.
If violence is justified because it prevents something worse, then the burden of proof becomes greater, not smaller.
The government must demonstrate necessity. It must minimize harm. It must constantly ask whether the means remain proportionate to the end.
Otherwise “national security” becomes a blank check.
The tenth lesson is deceptively simple: never say never.
Wars generate consequences that policymakers routinely fail to anticipate.
A conflict that is supposed to remain limited expands. An adversary expected to capitulate retaliates. An economic blockade intended to compel negotiations produces a new crisis. A waterway assumed to remain open becomes a battlefield.
The Iran war has already demonstrated how quickly events can move beyond the boundaries imagined at the beginning. The conflict has affected regional security, global energy markets and international shipping. The longer it continues, the more difficult it becomes to predict where its consequences will end.
That is not an argument against military action.
It is an argument against certainty.
McNamara’s final lesson is the most profound: you can’t change human nature.
We are tribal. We defend our decisions. We seek evidence that confirms what we already believe. We underestimate people we fear. We overestimate our own rationality. We confuse power with wisdom.
And perhaps most dangerously, we believe that our generation is different.
The weapons change. The technology changes. The presidents change.
Human beings do not change nearly as much.
That is why The Fog of War remains so unsettling more than two decades after its release.
When Morris and McNamara discussed the film at Berkeley in 2004, they were already being asked whether its lessons applied to the Iraq War. McNamara resisted treating history as a simple template, but the very question revealed the enduring relevance of his reflections. The eleven lessons were not a formula for predicting the future. They were warnings about recurring habits of mind.
We should resist the temptation to say that Iran is another Vietnam.
The more serious argument is that Iran may be revealing something more fundamental about American power.
A country can change its enemies without changing its habits.
It can develop better weapons without developing better judgment.
It can collect more intelligence without becoming wiser.
It can destroy more targets without becoming closer to peace.
That distinction matters because the public is increasingly uncertain about the purpose and direction of the war. A Reuters/Ipsos poll conducted in late July found that only one in three Americans supported the war, while 69 percent said Trump had failed to clearly articulate its objectives.
A war without a clearly articulated political objective creates an almost impossible standard for knowing when it has succeeded.
McNamara eventually understood that winning battles is not the same as winning wars. He understood that military superiority does not guarantee political wisdom. He understood that intelligence can be overwhelmed by assumption and that rationality can coexist with catastrophe.
McNamara giving a briefing
Most importantly, he understood something that powerful nations have difficulty accepting: We can be sincere and still be wrong.
That may be the deepest lesson of The Fog of War. McNamara learned the lessons of Vietnam late in life, after the costs had already been paid. We have the unusual luxury of hearing him explain them before the history is finished.
The question is whether anyone in Washington is listening.
The fog of war is not simply the confusion that descends upon a battlefield. It is the fog that settles over the minds of people who believe they can see the battlefield clearly.
And when a nation mistakes certainty for wisdom, history does not have to repeat itself.
Human beings will repeat it for us.