For some critics, the main revelation of the “Afghanistan Papers” published in the Washington Post last December is that America’s longest war was full of lies. Those who lied must be “held to account”, according to veteran left-wing journalist Katrina vanden Heuvel, lest a “culture of lying” grow. The inspector general for Afghanistan reconstruction condemned the “lack of honest public conversation between the American people and their leaders.”

Since we need to stop such futile and wasteful wars recurring, the reasoning goes, we should call out the lies that enable them, to deter liars in future. Is that really the wisest insight?

Launched 19 years ago into Afghanistan in retaliation for the 9/11 terrorist attacks, and then enlarging into a wider struggle across the “AfPak” border, the war grinds on still. According to the “Costs of War” project, it consumed approximately two trillion dollars (pricing in direct and indirect expenses), including $133 billion to build up Afghanistan, more in inflation-adjusted dollars than the Marshall Plan to rebuild postwar Europe. It has killed approximately 157,000 people, including more than 2,400 US troops, while over 20,000 American servicemen and women have been wounded.

For these investments, the returns are poor. The Taliban are undefeated and contest much of the country. After years of nation-building efforts, the country remains systematically corrupt. The heroin trade thrives. Whenever international forces leave, the ineffectual kleptocracy in Kabul probably won’t be able to galvanise the population to resist the likely onslaught to come. The US-led coalition can fund, arm and train people to govern, police or fight. Such technical upgrades, demonstrably, cannot transform their politics to harmonise with US interests.

The best security-related argument that could be made is that these campaigns made the country a dangerous place for international terrorists to base themselves in. This was always a strained logic. Disrupting such terrorism is possible without long-term, expensive adventures in fixing broken states, conducted in wildly difficult circumstances. Other than opening a terrorist front by accident in Iraq, Washington has not tried the same intensive, armed social engineering projects in other potential sanctuaries, such as Somalia or Yemen.

Training camps and headquarters in Afghanistan may have contributed in the 9/11 attacks but not in a straight line. Those attacks relied upon intermediate spaces that are now closely watched and policed, from meeting places in Hamburg to flight schools in Arizona. Most veterans agree the war was not worth fighting, and by decisive margins. They have a point.

Let’s face it: we don’t necessarily mind being lied to

Faced with this disappointing history, the outraged focus on bad faith. In the released interview transcripts generated by the office of SIGAR (the Special Inspector General for Afghanistan Reconstruction), evidently some of the makers of war practised deception actively and by omission to an internal audience and the world outside. Some participants exaggerated progress in security and development, and the winning over of Afghan hearts and minds. Not only was the war not being won, it was unwinnable. Under a cloak of misinformation, the deceivers muddled through.

And yet. let’s face it: we don’t necessarily mind being lied to. We mind failure, but not always falsification. The dirty truth about armed conflict is that deception is an inherent part of it. Obviously, misleading adversaries can help maximise the chances of victory: imagine the Sicily or Normandy landings without the deception operations that protected them.

War also, however, involves governments lying to their own people. The act of killing and dying to serve the polity is the ultimate political act. Because it is intense, it requires a process of creating mass consent. It cannot tolerate much nuance or complex judgment. Initiating, winning or terminating a conflict requires that leaders successfully carry opinion, painting a messy world in bold, bright colours, deflecting attention from anything that might soften the blame, or limit the stakes. Hence the urge to liken lesser adversaries to Hitler.

In liberal democracies, deception is a product of citizens’ contradictory demands. As American academic John Schuessler observes, policymakers lie not only from self-interest, but because their public wants them “to protect the national interest in a manner consistent with American values while at the same time minimising the risks and costs of war”. In an open, information-saturated society, this requires their complicity. People do not demand the full truth. Rather, they demand a prettier version of the truth that they can live with, a noble story bodyguarded by lies.

Looking back, lies offend us less in retrospect if we deem the cause and the outcome worthwhile. Consider past crises that in folk memory are recalled as “good” wars, or honourable episodes. Wartime leaders revered in the Anglosphere, such as  Churchill and Roosevelt, were dissemblers. When Churchill spoke of his belief in ultimate victory even after Dunkirk, he concealed his desperation and doubt to protect morale, clinging only to a remote hope of American entry.

Roosevelt deliberately forced a naval incident with a German submarine in the Atlantic, inflating the immediate Nazi threat to the western hemisphere to create a pretext for America’s entry into the Battle of the Atlantic in 1941. British intelligence helped tilt American opinion, forging documents suggesting Hitler’s designs on South America. To sustain the alliance with the Soviet Union and the public opinion that backed it, Roosevelt kept the Yalta Accords secret from the American people.

A nuclear world war was averted when President John Kennedy secretly agreed with Moscow to trade its withdrawal from Cuba with its withdrawal of Jupiter missiles from the soil of its ally, Turkey. If publicly agreed, that exchange would have provoked furious opposition and obstruction at home. Who would now rewind the tape of history, expose those lies or concealments at the time, and see how things pan out? So the issue is murkier that it seems. If our criterion for judgment is not an elevated concept of public truth-telling, but the national interest or the common good, then some lies are harder to forgive. These are not the deceits that governments inflict on their population. It is the wishful stories they — and we — tell ourselves.

To return to the Afghanistan papers, what emerges is less any grand, conspiratorial deceit than a wishful confirmation bias and discouragement of negative feedback from the ground. From above, determined to demonstrate victories, the White House and Department of Defence reported low US casualty figures as increased stability, rising casualties as part of renewed offensives, a reduction in suicide bombings as increased peace, a rise in suicide bombings as enemy desperation. Recall, too, the frequent promise of decisive campaign seasons.

From below, participants report being “shut down” about reports of corruption and its damage; a system “unaccepting of hard-hitting intelligence” and “incapable of taking a step back to question basic assumptions”; the misreporting of stabilisation projects; the manipulation of data; pressure to create “metrics” to promote rosy narratives; a failure to distinguish measures of effort from measures of success; departing commanders reporting mission success, in contrast to intelligence assessments, which were quietly overlooked. As a counterinsurgency adviser reported, “Bad news was often stifled.”

That stifling could also be internalised. As Lauren Johnson, a former Air Force public affairs officer recalled from her time devising messages for a provisional reconstruction team, “It became clear that ‘rebuilding’ an entire nation was a difficult, if not impossible task . . . it was my own heart and mind that needed convincing . . . my messages and Storyboards started to seem like an information campaign for myself.”

Even under the Obama administration, whose review and “surge” of troops in 2009-2011 was premised on a blunt acknowledgement that the war it inherited was going badly and needed repair, the hunt for positive metrics persisted. A senior National Security Council official recalled that this was “to make everyone involved look good, and to make it look like the troops and resources were having the kind of effect where removing them would cause the country to deteriorate”. In practice, it was hard to exclude the politics of selling the war — and the politics of careers — from the process of assessment.

The failure that helped both doom and prolong the military adventure in Afghanistan was that decision-makers persistently searched for, and invented, signs of success as a substitute for a cold appraisal of the problem. To have a coherent, achievable and clear objective, and to service it with knowing deceit is one thing. To engage in policy-based evidence-making while floundering in the dark and wilfully ignoring and discouraging negative feedback is quite another.

The stubborn will to believe persisted because Afghanistan is tied emotively to 9/11

Why did they deceive themselves? Beyond the general truth that we are all prone to bolstering prior views, it is also due to the politics of the war. The war was cursed by initial success, the fragility of being three goals up after ten minutes: the rapid routing of the Taliban and al-Qaeda, the return of Afghans from exile, the promise of the Bonn conference for new governance and reconstruction.

The stubborn will to believe also persisted because Afghanistan is tied emotively to 9/11 and the memory of that murderous day, giving a symbolic weight to a certain geography within Central Asia. In the collective amygdala of those who favour staying despite everything, withdrawal is linked to a resurgence of the threat that erupted on American soil. There is also the inertia born of a growing habit of military activism, and the reluctance of presidents to be seen to leave chaos, lose face and risk blame, a pressure that postponed Obama’s withdrawal and now Trump’s.

And having invaded, a developmental agenda took hold, the suspect notion that the US could only secure itself enough by building a strong, centrally governed state, a “new Afghanistan”, no less. War went beyond a limited raid to disrupt a threat, becoming a moral duty to Afghans with no clear limit in time, or sacrifice. All these influences made it hard to admit the impossibility of aims, the waste of lives and resources.

Again and again after 2001, sceptics warned that sooner or later, Washington would have to accept living with the Taliban rather than destroying it, returning less ambitiously to the tools of long-range counterterrorism and deterrence to dissuade the Taliban from supporting al-Qaeda’s larger jihad. It would have to disaggregate rather than aggregate enemies. In other words, the true choice was whether to accept this proposition then, or postpone that reckoning. Washington chose door number two, with all its costs.

The general public is also complicit. Most citizens hardly inquired about Afghanistan. Indeed, they hardly thought about it. Despite deceptions, it was still an open secret that the war in Afghanistan was a sad, sluggish disappointment. Dubious though metrics were, citizens hardly paid attention to them in the first place. Over-emphasising lies smells of evasion.

Consider the stark contrast with the Pentagon Papers leaked in 1971 that revealed systematic falsifications about the war in Vietnam. Americans cared more about those papers. There was a more energised civil society out of which emerged the anti-war movement of the era. And, more simply, they cared because that war was more lethal, and through conscription directly affected the populace.

Part of the tragedy of the Afghanistan campaign is that it appeared to be a sustainable and remote undertaking, far from ordinary lives. The state insulated its populace from it: waging it with professional soldiers and private contractors rather than with citizen-soldiers or the draft, funding it not directly through taxation but through borrowing, and urging voters to keep shopping rather than engage. People could live with lies, in other words, because the impression grew that combat operations, however limited in their effectiveness, can affordably go on and on. Ultimately, most believed it didn’t matter. They assumed they would be spared war’s consequences.

Given where two decades of war have led — the coarsening of politics, the militarisation of policing, the accumulation of deficits, the increase in Islamist militancy, the over-empowerment of the presidency, and the disillusionment of those who bear war’s brunt — this complacency may be the most grievous untruth of all.