That the conflict in Afghanistan wasn't an active issue in the election suggests that it is in danger of being regarded as a condition to be endured rather than a problem to be solved – much as the war in Iraq became before British troops withdrew. In their different ways, two new books – David Finkel's The Good Soldiers (Atlantic) and Sebastian Junger's War (Fourth Estate) – offer perilous insights into the nature of that condition. The Good Soldiers is the result of eight months spent with the US 2-16 Infantry Battalion in Baghdad, part of "the surge" confidently announced by President Bush in January 2007. War is an account of Junger's time embedded with a platoon of American soldiers at "the tip of the spear" in the lethal Korengal Valley in Afghanistan.

Writers are not obliged to deal with current events, but it happens that the big story of our times – the al-Qaida attacks on New York and the Pentagon, and the subsequent wars in Iraq and Afghanistan – is being told in some of the greatest books of our time. These books do not, however, take the shape and form often expected: the novel. So Finkel and Junger have their work cut out if their contributions are to squeeze on to a shelf of first-rate books that already includes Steve Coll's Ghost Wars; Lawrence Wright's The Looming Tower; George Packer's The Assassins' Gate; Rajiv Chandrasekaran's Imperial Life in the Emerald City; and Dexter Filkins's The Forever War.

Lower the bar only slightly and room would have to be made for books by Thomas E Ricks, Jane Mayer, Evan Wright and Ahmed Rashid. And there's no sign that the supply is about to dry up. August sees the publication of Jim Frederick's Black Hearts, which investigates the disintegration, under intolerable pressure, of a platoon of American soldiers of the 502nd Infantry Regiment in Iraq's "triangle of death" in 2005-06, culminating in the rape and murder of a 14-year-old Iraqi girl and the execution of her family by four members of the platoon.

As Packer put it in his recent collection of essays, Interesting Times: "The press redeemed in Baghdad what it had botched in Washington." Reportage, long-form reporting – call it what you will – has left the novel looking superfluous. The fiction lobby might respond: it's too soon to tell. A decade of literary silence followed the armistice of 1918. It wasn't until 1929 that a novel appeared that made imaginative sense of the first world war. Erich Maria Remarque's All Quiet on the Western Front answered an unspoken need and helped to create the conditions in which other war novels might, in the words of the hopeful Richard Aldington "go big". Since then, however, the lag between a given war and the appearance of books about it has shrunk. Norman Mailer's The Naked and the Dead appeared in 1948. In terms of its timing, Joseph Heller's Catch-22 (1961) was a strange and fortuitous case: a novel about the second world war that seemed to anticipate the absurdity of Vietnam. The defining prose work to come out of that conflict was a book of reportage, Michael Herr's Dispatches (1977), while the first Gulf war received its most memorable prose expression in Jarhead (2003), Anthony Swofford's account of his time in the marines.

The precedent set by Herr and followed, in off-kilter fashion, by Swofford, seems unlikely to be reversed. If there were ever a time when the human stories contained within historical events – what Packer calls "the human heart of the matter" – could only be assimilated and comprehended when they had been processed by a novel (War and Peace is the supreme example), that time has passed. As David Shields put it in his recent manifesto, Reality Hunger: "A while ago the imaginative thing – the supposedly great thing – would have been to write a 'novel about Vietnam', but I just feel in my bones how little I could read that." You don't have to sign up for Shield's anti-novel jihad to feel that what he says about Vietnam holds good for Iraq – only more so.

What about character and story? The characters are there in the non-fiction accounts, fully realised in flesh and (often awash in) blood, in the way that we expect fictional characters to be. Lawrence Wright has spoken of how, in the process of researching the 9/11 attacks, he came to realise that certain people could serve as "donkeys" who bore the weight of larger historical drives or circumstances. Part of the success of The Looming Tower derives from the way that these donkeys are presented as complex and developing individuals, never simply as beasts of narrative burden. And while their destinies fatefully converge on the twin towers in a way that is almost novelistic, the book's suspense and momentum do not reduce the idea of narrative to page-turning compulsion.

Although Finkel was often in the thick of the action described, he removes himself absolutely from his own narrative. In this respect The Good Soldiers is like a traditional third-person novel, with a near-omniscient narrator – or an Isherwood-style camera, recording but not judging. What this camera records – what the soldiers endure – almost defies belief. The combat is dreadful, the immediate aftermath worse: "Someone, maybe a medic, was pushing up and down on his chest so violently it seemed every one of his ribs must be breaking. 'You need to go harder and faster,' the doctor in charge told him. The medic began pushing so hard that pieces of Reeves's shredded leg began dropping on the floor." The long-term aftermath is worse still as the book's central character, Lieutenant Colonel Ralph Kauzlarich, visits the ruined soldiers and their families – recovering and not recovering – back in the States. "There was so much of Duncan Crookston missing that he didn't seem real. He was half of a body propped up in a full-size bed, seemingly bolted into place."

In the course of the book you see Kauzlarich – "Lost Kauz", as he becomes known – and other good men "disintegrate before your eyes". Their efforts are heroic and futile. Wright's idea of the donkey is enlarged so that the experiences of one group of soldiers encapsulate the larger quagmire of the US in Iraq – a quagmire that is tactical, strategic, moral and political. (Frederick does something similar in Black Hearts.)

The starkness and magnitude of Finkel's material demand an unerring control of tone. Even at its most matter of fact, his prose finds a hypnotic calm in the repetition of exposure to extreme danger: "Eyes sweeping, jammers jamming, the convoy moved along route Pluto . . ." At times there is an eerie, damaged lyricism: "Hours later, as the sun set, the sky took on its nightly ominous feel. The moon, not quite full, rose dented and misshapen, and the aerostat, a grey shadow now rather than the bright white balloon it had been in daylight, loomed over a landscape of empty streets and buildings surrounded by sandbags and tall concrete blast walls." One of these details acquires hideous poignancy later when a soldier is shot in the head; he survives but his head assumes the "dented and misshapen" aspect of the moon.

With touches like this Finkel demonstrates how the chaos of events can be given narrative shape by scrupulous observation and phrasing. A lesser but still thrilling book, War plunges the reader into the adrenalin-mist of combat. Like the soldiers around him, Junger is less interested in "the moral basis of the war" than the immediate experience of combat and its "twisted existential" ramifications whereby "each moment was the only proof you'd ever have that you hadn't been blown up the moment before". Often his senses were so overwhelmed by the experience that it was only by consulting video footage he had shot during firefights that he was able to understand and write up what had been going on. This feeds into another of Junger's interests: the complex mixture of military training and biochemical processes – the body's emergency surges and shutdowns – that enable a person to function in danger while the instinct for self-preservation programmes him to curl up in a ball or flee. Actually, it turns out not to be so complicated after all. Courage, Junger learns, is love: a willingness to lay down your life for others who, you know, would do the same for you, because in certain situations there is no such thing as "personal safety" ("what happened to you happened to everyone"). There is also the fact that combat is so "insanely exciting" that "one of the most traumatic things about [it] is having to give it up."

War is written in the first person; unlike Finkel, Junger is present in the events he records, but discreetly, unobtrusively. The most extreme contrast to Finkel's narrative self-effacement is the style of Dexter Filkins, whose The Forever War operates at a comparable level of literary excellence. Filkins is obviously an heir of Herr – he is so bad boy, so gonzo, which can be grating at first. Apart from a few details of transport and costume, this early glimpse of the Taliban could have been lifted straight from Hunter S Thompson's Hell's Angels: "Man, they were scary. You'd see them rolling up in one of the Hi-Luxes, all jacked up, white turbans gleaming; they were the baddest asses in town and they knew it, too."

A man who has "lived through everything, shootings and bomb blasts and death", Filkins is the latest incarnation of the reporter as renegade, "untethered, floating free, figuring out the truth by a different set of standards". Like Junger, he is willing to get to the place of maximum danger, but tends, when he gets there, to drift into digressions that wind us more tightly into the scene. At which point, a still more illustrious antecedent comes to mind: Ryszard Kapuscinski. (Perhaps we can also glimpse the ghost of Alan Moorehead, the great Australian reporter of the second world war.)

This willingness to digress, to operate in territory that shares a border with fiction, does not meet with universal approval. Several years ago I went to a talk given by Jon Lee Anderson, who had just published The Fall of Baghdad. During the Q&A afterwards I asked if he felt any tension between the New Yorker's famous emphasis on factual accuracy and the urge to embellish – even if it tugged one away from an objective reporting of the facts – that made Rebecca West and Kapuscinski great writers (if potentially unreliable reporters). Anderson dismissed the question with magisterial impatience. With the bullets flying, any thoughts of literary embellishment were luxuries he couldn't afford; his only concern was to report things accurately.

Filkins, I'm guessing, would have been more sympathetic, as even an atrocious incident, such as coming across the head of a suicide bomber who has detonated himself in a crowded market, can become a source of horror-comedy: "They'd placed it on a platter like John the Baptist's, and set it on the ground next to an interior doorway. It was in good shape, considering what it had been through . . . The most curious aspect of the face was the man's eyebrows: they were raised, as if in surprise. Which struck me as odd, given that he would have been the only person who knew ahead of time what was going to happen."

It's not just a question of tone. As with Kapuscinski's The Soccer War, the pieces in The Forever War often have the narrative shape and moral resolution of fiction. "Pearland" recounts an episode from the assault on Fallujah in which Filkins and a photographer are responsible for the death of 22-year-old Lance Corporal William Miller. The story ends with multiple layers of dreadful, unresolved irony.

Books of this kind make one feel thoroughly duped by Kathryn Bigelow's Oscar-winning The Hurt Locker. As with the HBO adaptation of Evan Wright's Generation Kill (written by David Simon and Ed Burns), the viewer is immersed totally in the experience of the American military in Iraq. Both film and TV series are relentlessly gripping, especially The Hurt Locker, where every bit of trash – and there's a lot of trash – is potentially life-threatening. Indeed, the film is so nerve-shreddingly tense that it's only when you re-emerge into the safety of daylight that you realise how you've been manipulated, how shallow the experience has been. There is a thematic continuity here within Bigelow's work: The Hurt Locker serves up a military equivalent of the thrill-trips that Lenny Nero was hustling in her earlier Strange Days. Lenny sells virtual reality experiences of everything from a girl showering to armed robbery. And that – right down to the same camera techniques – is what we get here. The new twist is in the nature of the simulated environment: all the thrills and spills of combat and bomb disposal in the privacy and safety of your own home-entertainment environment. So impressive is the technical accomplishment that one forgets that the action, while ostensibly unfolding in the context of a real and recognisable war, is operating safely within the absurd liberties of Hollywood convention. As if life as a bomb-disposal expert were not adrenalin-inducing enough, we are treated to a Bourne-style interlude in which William James implausibly pulls on a hooded sweatshirt, takes a pistol and goes on a one-man search for vengeance/justice at night, in Baghdad – and makes it back in one piece.

The series Generation Kill is, along with everything else, a sustained critique of the structural and conventional fictions of The Hurt Locker. Taking no liberties with the facts of Wright's account, it follows a convoy of US marines as they make their way from Kuwait to Baghdad. Certain characters have more screen-time than others but there are no heroes. As in a platoon, everything comes down to teamwork and ensemble playing. The action is never contrived to assume the shape imposed by the demands of a good story. This is one of the reasons why, ultimately, the immersion in the experience of war is more complete than in The Hurt Locker. Despite their expertise and marksmanship, the extent to which the marines control their own destinies is minimal; it pretty much ended, in fact, before the series began, when they signed up. From the start we are sealed within the acronym-intensive argot and worldview of the USMC. Our point of view is absolutely that of the marines. The lessons dished out by their experiences are never moralistic but, as the situation deteriorates around them, the larger ethical and strategic impossibility of their position and purpose becomes unavoidable. We are back to the quandary observed by Finkel in The Good Soldiers. We are also back, more generally, to the relative strengths of non-fiction over fiction. Of course one could easily imagine a novelist doing without any of the liberties enjoyed by Bigelow – but we would be left, then, with a novel that was almost a carbon copy of the best of these non-fiction books. For the assumed skills of the novelist – an eye for telling detail, stylistic flair and so on – are deployed in abundance by many of these reporters, at least the ones who are (there's no dodging this bullet) American.

Within every comparable category or type of book on Iraq and Afghanistan the Americans do it better than their British counterparts. On either side of the Atlantic the books by journalists are, naturally, better than those by the people they are writing about. It is clear from Generation Kill that Lieutenant Nathaniel Fick is a remarkable officer and human being. In his partial autobiography, One Bullet Away, however, Fick is not able to impose his authorial personality on his version of the story from which he emerges with so much credit in Wright's account. Similarly, Desperate Glory – British journalist Sam Kiley's Jungeresque account of his time in Helmand with Britain's 16 Air Assault Brigade – is a better piece of writing than The Junior Officer's Reading Club, former soldier Patrick Hennessy's memoir of his tours of duty in Iraq and Afghanistan. This is inevitable; we don't expect Wright and Kiley to be able to shoot more accurately or march further in full equipment than Fick or Hennessy. But once we start comparing like with like – soldier with soldier, journo with journo – the Americans come out unambiguously ahead.

The reasons for this are not hard to fathom. American writers are the beneficiaries of the deep pockets of the magazines that initially sponsored them. In this respect the situation has not changed greatly since Vietnam when the photographer Larry Burrows was working for Life. What his son Russell called "the real luxury" of that gig – that the magazine was "prepared to let somebody go and work for however long it took" – still holds true for print journalists lucky enough to be working for Rolling Stone (Evan Wright), Vanity Fair (Junger) or the New Yorker (Packer).

More generally, American journalists writing about the US military are the beneficiaries of the all-round flexibility and versatility of American English as deployed by the soldiers on whose lives they depend. Officers and non-coms alike share a common idiom which is varied and animated by the racial and cultural make-up of the army. In the British military, by contrast, the lack of this shared linguistic medium reflects the basic class division of the army, between officers and men, toffs and proles. Instead of variety there is a straight choice. And this applies not just to reported speech but to the register adopted by writers when operating outside the class perimeter of inverted commas. As can easily happen when choice is demanded, the worst possible result is compromise that rinses out everything that might make either idiom compelling.

Kiley is "mad keen" to get the job done, but even when the experiences he records are terrifying, the writing is always comfortably unthreatened, except by clichés which are often, as they say in the military, danger-close. "The air fizzes and crackles with bullets. There seems to be no space between them as if they are being poured from a hose. Rounds are smacking into the ground; the dust is leaping around their feet. Des can hear the fizzing sound made by bullets which are within a foot of his ear. He can feel the hot whip of them on his face." Junger is as experience-dependent as Kiley but his prose ("he saw a line of bullets stitching towards him in the dirt . . .") works like one of Lenny Nero's virtual trips, sealing us within the experience he describes.

This is not to say that, by turning their attention to Afghanistan or Iraq, American reporters and journalists are on to a sure-fire success. When Jon Krakauer became interested in the story of Pat Tillman he must have thought that he had found (in Wright's terms) the perfect donkey: all-American boy wins lucrative pro football deal but, after 9/11, chucks it in to join the army and goes to Afghanistan, where he is killed in an ambush. Even more of a hero. Then word begins to creep out that he was killed by friendly fire, and the military try everything in their power to conceal the truth.

It's a potentially great story, and even though Where Men Win Glory reveals Krakauer's limitations as a writer – for the historical background, he gulps down hunks of Steve Coll and Lawrence Wright without ever adequately digesting them – it remains an interesting failure in unexpected ways. Krakauer sees that the military want Tillman to fit into their own heroic narrative, both specifically (the ambush) and generally (football star sacrifices career to join army and then sacrifices himself). But it is clear that Krakauer has seized on Tillman as the latest incarnation of the ideal of rugged and tragic individualism that made his earlier books Into Thin Air (about a doomed Everest expedition) and Into the Wild (the story of Chris McCandless's death in the Alaskan wilderness) so compelling. Viewed in this light the book compounds the kind of exemplary appropriation that it investigates.

One of the Tillman family's grievances is that the army – specifically a commanding officer who was also an evangelical Christian – overrode Pat's explicit wish for a secular funeral. Later, after the family had refused to accept the findings of several investigations into Pat's death, that same commander gave an interview in which he suggested that the Tillman family's continuing dissatisfaction was due to its lack of religious faith.

In the larger scheme of Krakauer's book it's a fairly minor point, but the Christian commander turns out to be none other than Ralph Kauzlarich, the enormously sympathetic central character – the donkey carrying the heaviest load – in Finkel's The Good Soldiers. Just as characters interconnect with each other within a novel, so these non-fiction books and real-life characters interconnect with each other to form an epic, ongoing, multi-volume work in progress.

The biggest question mark about this proto-book concerns the way in which it is illustrated. As Packer wrote in the essay quoted earlier, the press may have excelled itself in Baghdad, but "Iraq has not been a photographer's war". Really? When there are so many strong pictures coming out of the current wars by Sean Smith, Michael Kamber, Tim Hetherington and others? (Hetherington was with Junger in Afghanistan and co-directed their forthcoming documentary Restrepo.) Perhaps these are the exceptions that prove the rule, for Packer, it's important to note, is talking about photographers, not photography. In Iraq and Afghanistan we are perhaps glimpsing the end of the era of the combat photographer as a special category of occupation, the twilight of the photographer as novelist in the way that Capa (whose famous photo from the Spanish civil war is now believed to be a fiction) and Eugene Smith were visual novelists. Current photography from the frontline is defined absolutely by what it is of rather than who it is by. No photographer has been able to stamp a visual identity on what he depicted in the way that Capa or Tim Page managed, respectively, on D-Day or in Vietnam. Perhaps photographs are now simply too ubiquitous for that. So ubiquitous that, in a passage of Finkel's book, "photographs" refers not to actual physical records of the kind collected by Wilfred Owen (who carried photos of the dead and injured in his wallet) but a way of seeing, a state of damaged mind. Suffering from post-traumatic breakdown, one of the most heroic of Finkel's soldiers explains that he keeps seeing "photographs . . . Like a picture of Harrelson burning, in flames. I can't get that out of my head . . . It's just a slideshow in my head."

The debate about current combat photographs is less about their quality than whether it is appropriate or in good taste to publish them. Last year the Associated Press caused a fire-storm of controversy by distributing a photograph from Afghanistan taken by Julie Jacobson. Lacking any of the formal elegance of Burrows, just about in focus, it was unremarkable in every way – except that it showed 21-year-old Lance Corporal Joshua Bernard in the process of dying from wounds after being hit in the legs by an RPG. Bernard's family were adamant that they did not want the picture published and were outraged when AP went ahead anyway on the grounds that it showed the human reality of war.

Filkins, Finkel and others witness events just as harrowing, and describe them in more explicit detail. Their verbal records of these events became tributes for which they receive the gratitude of the bereaved and maimed. Anyone who was there with a camera and an auto-wind could have taken a picture of the quality of Jacobson's. Only a few supremely gifted – and courageous – individuals could have recorded the deaths of Miller or Reeves with the skill and power of Filkins or Finkel. They are, to adapt a phrase of Martin Amis, "moral artists."

The phrase is from an essay in The Moronic Inferno in which Amis claims that the non-fiction novel, as practised by Mailer and Capote, lacks "moral imagination. Moral artistry. The facts cannot be arranged to give them moral point. There can be no art without moral point. When the reading experience is over, you are left, simply, with murder – and with the human messiness and futility that attends all death." The essay is an old one, and the point can now be seen to contain its own limitation and, by extension, refutation. We are moving beyond the non-fiction novel to different kinds of narrative art, different forms of cognition. Loaded with moral and political point, narrative has been recalibrated to record, honour and protest the latest, historically specific instance of futility and mess.