Most of the stories told about Benjamin Moore, 23, at his funeral started in a bar and ended in a laugh. Invited to testify about his life from the pews, friend, relative, colleague and neighbour alike described a boisterous, gregarious, energetic young man they'd known in the small New Jersey town of Bordentown since he was born. "I'll love him 'til I go," his granny said. "If I could go today and bring him back, I would."

Grown men choked on their memories, under the gaze of swollen, reddened eyes, as they remembered a "snot-nosed kid" and a fidget who'd become a volunteer firefighter before enlisting in the military. Shortly before Benjamin left for Afghanistan, he sent a message to his cousin that began: "I'm about to go into another country where they hate me for everything I stand for." Now he was back in a flag-draped box, killed by roadside bomb with two other soldiers in Ghazni province.

The church was packed to capacity and at least a couple of hundred waited outside. The procession to the cemetery began with firetruck horns and was lined with well-wishers. He went under the ground with several military medals and the posthumous titles of chief of Hope Hose fire company and the "honorary mayor" of Bordentown.

There is a reverence for the military in the US on a scale rarely seen anywhere else in the west that transcends political affiliation and pervades popular culture. On aeroplanes the flight attendant will announce if there are soldiers on board to great applause. When I attended a recording of The Daily Show, John Stewart made a special point before the show of thanking the servicemen in the audience.

But while the admiration for those who serve and die may be deep and widespread, interest in what they are doing and why they are doing it is shallow and fleeting. During November's midterm elections it barely came up. In September just 3% thought Afghanistan was one of the most important problems facing the country. When Pew surveyed public interest in the war over an 18-week period last year, fewer than one in 10 said it was the top news story they were following in any given week, including the week Stanley McChrystal – the four-star general commanding troops in Afghanistan, was fired. The country, it seems has moved on. The trouble is the troops are still there.

"The burden for this war is being carried by such a small slither of society," explains Professor Christopher Gelpi, who specialises in public opinion and foreign policy at Duke University. "Unless you know someone in this war, live near an army base or know of someone who has died, then it is possible for the public to ignore it. People are very disconnected from it."

And when they do pay attention, they do not like what they see. Polls in December reveal that 63% oppose the war, 56% think it is going badly (with 21% believing it is going very badly), and 60% believing it was not worth fighting. Indeed opposition to the war is now on a par with Iraq.

This statistical data chimes with Gelpi's qualitative findings about people's attitudes towards the war. In a study he conducted in last spring, he found that people know very little about the war but "view it through the filter of Iraq". "Those who have made up their minds about Iraq," he concludes in the paper, The Two-Front Homefront, "appear to extrapolate these views to Afghanistan and are reluctant to attend to new information on the conflict."

But while that popular elision is understandable – no sooner had the war in Afghanistan been launched than the war in Iraq was being touted – it is problematic. Afghanistan is not Iraq. Indeed, in many ways, the lessons from Afghanistan are more profound, ingrained and urgent. Globally speaking, opposing the war in Iraq was not even remotely contentious. Significant majorities in almost every country, with the exception of the US, were against it. Before it was inept it was already illegal, and before it was illegal it was already illogical. It was wrong on its own terms, and its own terms were rooted in a lie.

But there were relatively few lies told in the selling of the Afghanistan war. This, remember, was the "smart war." Both George Bush's war and Barack Obama's war. A war supported by Nelson Mandela, Muhammad Ali and Susan Sontag. A "war of necessity", which had the backing of almost the entire political class on both sides of the Atlantic.

A war only a single national politician in the US dared oppose. In her speech to the House of Representatives on 14 September 2001, after which she received numerous death threats, Barbara Lee warned: "We are not dealing with a conventional war. We cannot respond in a conventional manner. I do not want to see this spiral out of control … If we rush to launch a counterattack, we run too great a risk that women, children and other non-combatants will be caught in the crossfire … Finally, we must be careful not to embark on an open-ended war with neither an exit strategy nor a focused target. We cannot repeat past mistakes."

This, in no small part, is why it has not become an electoral issue This was a bipartisan effort – and all the worse for it. When it was launched, many claimed parentage; in its failure, it is an orphan. "It's not become a political issue because the Republicans are more supportive of the war than Obama is," explains Gelpi. "So all he has to worry about is a rebellion from his left." The potential for such a rebellion certainly exists. But its likely potency, at this stage, remains suspect.

But to engage with what went wrong would demand a sharp reckoning with why so many thought it would was right to begin with. The country would have to interrogate its militaristic reflexes and proclivities, and face the fact that while there were few good or certain options after 9/11 (ranging from the diplomatic to containment) this was one of the worst – and the others were never seriously considered.

For as the principal retaliatory response to the terror attacks of 9/11, it has failed. It hasn't brought liberty, democracy or stability. It has killed untold thousands of civilians: untold because they are regarded as expendable. And not only has it not captured the perpetrators of the terror attack, there are far more acts of terrorism globally today than there were in 2001, in no small part because of the chaos wrought by the war on terror.

Back at the Trinity United Methodist church in Bordentown, the minister ended the service with the hymn Let There Be Peace on Earth and Let It Begin With Me.

Elsewhere in the country, small communities like this weep every week without respite as bodies from a global conflict return to become a local tragedy without, apparently, altering the national mood. Like a stone thrown into a pond the ripples go only so far and then fade away.

Back in 1971, during the Vietnam war, John Kerry famously testified before the Senate foreign relations committee. He put the question: "How do you ask a man to be the last man to die for a mistake?" Forty years later, the answer appears to be that you simply stop paying attention to their deaths.

It seems American soldiers are not so much dying for their country, but because of it.