How bleak was my valley?

You don't call a book War - no article, no adjective - unless your goal is to stake a claim for a place in the canon of literature on the subject. Sebastian Junger has done just that with his new book, but it is an ambition easier stated than fulfilled: the broad and sweeping title suggests an enormous canvas, but the focus here is on a small group of men, fighting (and dying) for a narrow slice of Afghanistan.

When Junger, a square-jawed aficionado of all things manly who shot to fame with his 1997 blockbuster The Perfect Storm, arrives in Afghanistan, he naturally seeks out the country's most dangerous terrain: the Korengal Valley, on the border with Pakistan just north of the Khyber Pass. Only 10km long and 2km wide, the valley is a conduit for Taliban forces crossing into and out of Pakistan, and as such an important tactical asset. But it is also extremely difficult to control, thanks to the forbidding topography - which presents would-be insurgents with innumerable positions for attack - and the famously fierce independence of its residents, whose hostility to outsiders extends to the Afghan government and police, who rarely if ever set foot there. "The Korengal Valley," Junger writes, "is sort of the Afghanistan of Afghanistan: too remote to conquer, too poor to intimidate, too autonomous to buy off."

When Junger arrives at the Korengal Outpost, an American base a few miles into the valley that was already "considered one of the most dangerous postings in Afghanistan," he finds the commanding officer, Captain Dan Kearney. "I ask him who is pushed farthest out into the valley and he doesn't hesitate ? I tell Kearney those are the guys I want to be with." Of course it is. He ends up embedding with Battle Company of Second Platoon, and over the course of 15 months he returns for five separate visits.

Battle Company is regularly set upon by insurgent fighters; firefights and mortar shelling are frequent occurrences. Alone and beleaguered, the men present a tableau of desperation, boredom, and disgustedness, punctuated with fits of adrenalin and heroism. Their unofficial slogan has become "Damn the Valley". Some of the accounts of combat are gripping, with Junger depicting soldiers, sometimes shirtless or without body armour or while smoking a cigarette, rushing to return fire over the tops of sandbags - punch-drunk under fire and high on the dire thrill of battle. The most dramatic writing comes when a Humvee carrying Junger is hit by a roadside bomb: the incident stirs some of his most vivid description and some of his most pointed insights. Travelling down these roads, where IEDs are abundant becomes "a twisted existential exercise where each moment was the only proof you'd ever have that you hadn't been blown up the moment before."

The emotional sinew of the book is the connection the soldiers make with one another - isolated from the forbidding landscape, the hostile population and from their own comrades elsewhere in Afghanistan - and the connection Junger makes with them, particularly with one rudderless and laconic Private named Brendan O'Byrne, whose biggest fear seems to be returning to civilian life rather than getting killed far from home. Junger is taken not only with the idea of soldering, but also with the soldiers themselves. Repeatedly, one finds outsized descriptions of the men's physical aspect. One man seemed "capable of going to the Olympics in virtually anything". Another is "an insanely fit Lieutenant Colonel of Cherokee descent". Dig it, the US Army does not employ weaklings.

And beyond that, there is much praising of their courage, and the age-old notion that each soldier is only "doing his job" and "I'm not doing for them anything they wouldn't do for me." These things are no doubt true, but they are also somewhat trite. Junger is largely apolitical about the engagement in Afghanistan, as are the men he is covering. "The moral basis of the war doesn't seem to interest soldiers much," he reflects, "and its long-term success or failure has a relevance of almost zero. Soldiers worry about these things about as much as farmhands worry about the global economy, which is to say, they recognise stupidity when it's right in front of them but they generally leave the big picture to others." He and they seem to have the common American opinion that the fighting in that country is worth doing, as long as it is being done right. But doing it right isn't the same thing as winning, as Junger is well aware, and the events that he recounts in the Valley are both deadly and discouraging. In the five years since US forces set up shop in the Korengal, 42 soldiers have been killed - one for "every hundred yards of forward progress in the valley" - as have who knows how many Afghans. The received wisdom, even among the soldiers doing the killing, is that every dead woman or child will bring at least one new recruit into the ranks of the insurgents - making this particular engagement, at least, look like a rather counterproductive affair.

"Public affairs will tell you," Junger notes later, "that the Taliban are getting more brutal because they're losing the war, but pretty much everyone else will tell you they started out brutal," he writes: "More American soldiers were killed that year than in any year previous, but if you pointed that out, you were simply told that it was because we were now 'taking the fight to the enemy'. That may well have been true, but it lacked any acknowledgement that the enemy was definitely getting their s*** together. I thought of those as 'Vietnam moments'. A Vietnam moment was one in which you weren't so much getting misled as getting asked to participate in a kind of collective wishful thinking. And we reporters had our own issues. Vietnam was our paradigm as well, our template for how not to get hoodwinked by the US military."

Since he was 13 years old when the last Americans absconded from the roof of the embassy in Saigon, what Junger really means here is not so much "Vietnam moments" as those moments depicted in books about the Vietnam War. So perhaps we should think of these as Dispatches moments, after the journalist Michael Herr's classic memoir of that war. Herr's writing stamped a template that has been endlessly imitated and rarely matched, and his style casts a long shadow across War. When Junger's writing its at its best, it sounds all too often like he's almost channelling Herr, as in this passage: "Javelin rockets and hand grenades and 203s and cases of linked rounds for the .50 and the 240 and the SAW. It seemed like there was enough ammo ? to keep every weapon rocking for an hour straight until the barrels have melted and the weapons have jammed and the men are deaf and every tree in the valley has been chopped down with lead."

The "Vietnam moments" in Dispatches capture an equally dispiriting wilful optimism among the senior brass: "The mission council had joined hands and passed together through the looking glass," Herr writes. "Our general's chariot was on fire, he was taking on smoke and telling us such incredible stories of triumph and victory that a few high-level Americans had to ask him to just cool it and let them do the talking. A British correspondent compared the Mission posture to the captain of the Titanic announcing, 'There's no cause for alarm, we're only stopping briefly to take on a little ice.'"

It's not only from the lofty perch of geopolitics that the war in Afghanistan sometimes looks like a bad replay of Vietnam: from the ground, at the sharp end of the American presence in Afghanistan, at least as Junger presents it, it may look that way all the time. The paradigm of war on the ground has not shifted terribly far in the time since Vietnam - and certainly less so than the dramatic shift that took place between the Second World War and the quagmire in Indochina. There were Chinook helicopters then, there are Chinooks now. Foot soldiers used to marvel at the Air Cavalry's devastating mike-mike guns, and those are the same guns tearing up the hillsides of Afghanistan today. And soldiers still carry a variation of the M16 rifle. In a war, a lot depends on hardware, even meaning. Even Junger, musing on the might of American firepower, intuits a metaphor for the American project in Afghanistan. "Each Javelin round costs $80,000," he observes, "and the idea that it's fired by a guy who doesn't make that in a year at a guy who doesn't make that in a lifetime is somehow so outrageous it almost makes the war seem winnable."

Whether or not the war is winnable - or what it would even mean to "win" - the Korengal Valley, it now seems, is not. Last month the American army dismantled the outposts where Junger watched soldiers lose their lives, stating that the territory was of no strategic value. After the withdrawal, reporters from the New York Times interviewed more than a dozen men who served in the Valley. Their conclusion? "Not one thought it was a mistake to close the outpost."

Brian Gallagher is a writer in New York.