Had he lived, Orwell would have turned 99 next month. The spangled Edwardian literary generation of which he was a part, and which dominated English literature in the half-century after his death, is dead and gone. Alone among that gentlemanly throng - Waugh, Connolly, Powell, Greene, Spender - all of whom were known to him and several of whom were personal friends, Orwell has burrowed into the popular consciousness, entered the language and the interior lives of people who barely know that he existed. This is quite an achievement, comparable with Dickens's impact on the cultural landscapes of the 19th century, and a process of mental colonisation, moreover, that shows no sign of slowing down or diluting itself to the point of vagueness. We remember Dickens for his ability to make us laugh and for his moral authority. We remember Orwell for his moral authority, too, but also remain starkly conscious that it has a direct, rather than an abstract, connection to the world we inhabit.
At the same time, it is possible to admire someone for their moral authority without quite knowing of what that moral authority consists. Looking over the newspaper comment pages from autumn last year, for example, one was not in the least surprised to find Orwell being invoked as a flail with which to whip "bleating" opponents of the post-11 September military action in Afghanistan. Orwell, it may be said, is always good value for the armchair strategist. His writings spill over into nearly every area of public life, and if you look carefully enough there is pretty sure to be a quotation to fit any exigency. It would be perfectly possible, for instance, to make him out as both a supporter of war - he was notably hard-headed about the saturation bombing of German cities - and someone who regarded the very act of picking up a rifle as morally indefensible. In either case, the value of his observations rests on his personal experience, unlike most of those currently pontificating on the international situation, of having thrown bombs into trenches with the intention of killing the men in there.
The irony of Orwell's recent role as quotation-supplier to military apologists - an Observer piece reproduced some particularly injurious remarks about left-wing defeatism made in the aftermath of Dunkirk - is that he should be so consistently used to shore up the defences of the right. As Christopher Hitchens shows in his new study, Orwell's Victory, this process reached its nadir in 1983 when, zealously misquoted and misrepresented, Orwell was suborned into the ranks of the American Star Wars nuclear defence programme by its arch-propagandist, Norman Podhoretz. And yet, for all his posthumous reinvention as court philosopher to the CIA, he remained a paid-up left-winger, deeply suspicious of American consumer capitalism, while realising that the "liberty" offered by the west was less of a swindle than the political arrangements prevailing in eastern Europe. Like many of the positions he took up, Orwell's attitude to America was a great deal more complex than selective quotation may allow it to appear, and Hitchens has a tremendous time juxtaposing Podhoretz's garblings with another statement of Orwell's, written in the same year as the essay cited by Podhoretz, to the effect that although Europeans may have to accept US domination, "they ought to realise while there is yet time that there are other possibilities". In fact, Orwell's fix for the problem of American world domination turns out to be "a socialist United States of Europe".
As the foregoing may indicate, trying to deduce what a man 50 years dead might have made of political events played out long years after his passing is a risky business at the best of times. There is an entry in Anthony Powell's Journals: 1982-1986, for example, written shortly after the Falklands war, in which Powell speculates that Orwell would have supported the sending of the task force. Powell, it should be pointed out, knew Orwell intimately and was better qualified to pronounce on his likely opinions than anyone then living. He was, additionally, one of the few people in whom Orwell, legendarily reserved even with his friends, seems to have been prepared to confide, whether this opening up involved details of his sex life ("Have you ever had a woman in a park?") or bracingly prosaic thoughts on the Spanish civil war (Orwell conceded that the loyalties of individual Spaniards largely rested on where in the country they lived).
Even so, you rather quail before this assurance, just as, 20 years later, you wonder whether fast-forwarding an essay, written at a time when Britain was in serious danger of invasion, into the age of 21st-century power politics is not a rather dangerous exercise in historical relativism. Yet such is our reliance on Orwell - on his moral infallibility, his sheer pervasiveness - that the questions continue to be asked: what would Orwell have thought about the Afghan bombing campaign? About militant Islam? About the Blair government?
There is a difference, perhaps, between a quiet insistence on Orwell's "relevance", which Hitchens performs by way of a few ominous despatches from North Korea and Zimbabwe, and Decalogue-type pronouncements on "what George would have thought". The "victory" of Hitchens's title has several shadings: literary, political, moral. Orwell would probably not have wanted to make these distinctions. Taken together, they describe what to Hitchens is Orwell's undisputed status as top dog, the one who triumphed, the one who was right - and continues to be right, and will always be right - in the great arguments and conflagrations of the age. Simultaneously, Hitchens is keen to trash the vision of the secular saint perpetuated by the hagiographers of the 1950s. "I sometimes feel as if George Orwell requires extricating from a pile of saccharine tablets and moist handkerchiefs," he writes early on.
There follows a brisk, pamphlet-length canter through most of the main arenas of modern Orwell studies: Orwell and Empire (where our man is marked down as one of the founders of post-colonial studies); Orwell and the left (an inspired catalogue of naming and shaming, this, with spectacularly compromised appearances from Edward Said and the late Raymond Williams); Orwell and the right; Orwell and America (his "missed opportunity" according to Hitchens); moving on into discussions of Englishness, feminism, the famous (and famously innocuous) "list" of 1940s fellow-travellers, influences on the Angry Brigade of the subsequent decade, and ending up, in the wake of the Sokal hoax, with a chapter on Orwell the anti-postmodernist.
Hitchens is a close reader, both of Orwell's own writings and those of his critics. The paragraph about the Spanish civil war that his alert eye fishes out from Raymond Williams's 1971 Modern Masters study is worth quoting in full. Williams is referring to the events in Barcelona in May 1937, when the left-wing but anti-Stalinist POUM militia, for which Orwell had fought and been wounded, found itself proscribed by the Republican government on the grounds that it was fomenting a social revolution inimical to current Soviet foreign policy.
"Most historians have taken the view that the revolution - mainly anarcho-syndicalist but with the POUM taking part - was an irrelevant distraction from a desperate war. Some, at the time and after, have gone so far as to describe it as deliberate sabotage of the war effort. Only a few have argued on the other side that the suppression of the revolution by the main body of Republican forces was an act of power politics, related to Soviet policy . . ."
Even 30 years after it was written, with Williams dead and the whole Marxist-historiographical tradition in which he laboured reduced to ashes, one ponders this with a fair amount of incredulity. Who are "most historians"? "Suppression" is certainly one way of describing the presence of Soviet- sponsored hit squads on the streets of Barcelona, mass imprisonment, rigged trials and summary executions. Then there is the marvellous detachment of "related to Soviet policy", as if what happened in Spain early in the summer of 1937 had only some faint, incidental connection to Russian foreign policy rather than being a direct result of it. A similar vein of subterfuge runs through Isaac Deutscher's subtly disparaging essay "1984 - The Mysticism of Cruelty" (from Heretics and Renegades and Other Essays, 1955). Tracking Orwell's disillusionment with the Marxist left back to the Stalinist purges of the late 1930s, Deutscher imagines that he projected this spectacle on to the future, "and he saw it fixed there for ever, because he was not capable of grasping the events realistically, in their complex historical context".
Deutscher goes on to complain that this "piercing shriek" - his description of Nineteen Eighty-Four - has frightened millions of people. "But it has not helped them to see more clearly the issues with which the world is grappling; it has not advanced their understanding." Yet what was there, in the aftermath of the gulags and the crimes committed in the name of proletarian solidarity, left to be understood? It is so much easier, when faced with something unpleasant one would sooner not see, to talk about realism and complex historical contexts.
There is a wholly legitimate criticism that can be aimed at Orwell from the left. This is to complain at the posthumous reputation-broking that has allowed him to dominate the literary 1930s to the exclusion of nearly everyone else. Evelyn Waugh once protested, in an early 1950s review of Stephen Spender's autobiography, that the members of the Auden-Isherwood-Spender axis had "ganged up" to capture the decade for themselves. Half a century later, it would be accurate to say that Orwell's admirers have since ganged up to capture it for Orwell, that the unattached, marginal figure of the prewar era has gradually moved centre stage, while a swathe of contemporary left-wing literature of the type that he disparaged in The Road to Wigan Pier (1937) is largely ignored. This claim underpins leftist literary histories of the period, such as Andy Croft's agreeably spiky Red Letter Days: British fiction in the 1930s (1990).
But Deutscher's criticisms are more basic, more fundamental to that whole 20th-century left-wing angle on world history, and, as such, much less allowable. In slight mitigation, it can be said that Deutscher, who served with him as a war correspondent in the occupied Europe of 1945 and had the opportunity to observe him at close quarters, did have one very good point about Orwell, a personal point about the way in which some of his psychological compulsions infiltrated his work.
This is not to reduce Orwell to the status of a purveyor of simple absolutes. As an early advocate of decolonisation, he was sharply aware that "independence" might not mean very much to a small, backward nation in thrall to powerful neighbours. One could set Burma, the location for his five-year stint as an imperial policeman, notionally "free", but that did not mean she could automatically determine her own destiny. And what if she opted to determine that destiny in a way that struck at the nation that freed her?
A similar complexity runs through his attitude to pacifism and the pacifist movement of his time. On the one hand, he could be provoked into blunt, adversarial assertions: "pacifism equals objective pro-fascism", for example, which even a devoted fan would have trouble swallowing. On the other, he maintained that one of the merits of the British political system was that the authorities could allow a publication such as Peace News to be sold openly, in the knowledge that 95 per cent of the population would never read it.
Pacifism was only tenable, he believed, if the pacifist worked out, and was prepared to abide by, the logical consequences of his or her non-violence (Gandhi, for instance, whom Orwell regarded with deep suspicion, was forced to concede that the only way in which the Jews could escape the attentions of the Nazis would be to commit collective suicide.) If your enemy is prepared to use terrorist tactics to blow up thousands of innocent civilians, what steps are you prepared to take in your defence? If, in addition, your country harbours thousands of citizens who actively support this action, what are you going to do about it? These, you feel, are the kinds of questions Orwell would have been asking last autumn, and it is worth pointing out that no one on the anti-war left has yet got round to answering them.
All of which brings us back to the 21st century, and a world in which Animal Farm and Nineteen Eighty-Four retain an altogether ominous significance. Without rushing to Peter Davison's monumental, 20-volume edition of the collected works for guidance, it can be said, perhaps, that the ironies of last autumn - Muslims bombing other Muslims in the name of anti-imperialism, Americans dutifully attacking a regime they had previously encouraged - would not have been lost on him, and that whatever he said would have brought little comfort to either side.
One of Orwell's most attractive features is his ordinariness, but it is an ordinariness that can be deeply idiosyncratic. Here is a final pair of quotations, one noted by Hitchens, the other not:
Obviously one must not kill children if it is in any way avoidable, but it is only in propaganda pamphlets that every bomb drops on a school or an orphanage.
It is a pathetic, doglike face, the face of a man suffering under intolerable wrongs.
The second sentence, for the record, was written - of all people - of Adolf Hitler, in - of all times - March 1940. One could imagine Orwell writing something very similar of the portraits of Osama Bin Laden. To return to the "What would George have thought?" debate, back in that piece in the Observer last October, Geoffrey Wheatcroft suggested that every British soldier sent to Afghanistan should be issued with a volume of Orwell's essays to carry in his rucksack. This is a fine and enlightened scheme, worthy of large-scale public subsidy, but somehow you doubt that the result would be quite what Wheatcroft - or anyone else from the belligerent right - has in mind. Never mind Orwell's enemies, most of whom are now discredited beyond the point of intellectual redemption: it is sometimes necessary to rescue a writer of the kind Orwell has now become - a kind of super-literary presence stretching out into the whole of recent history - from his friends.
Orwell's Victory is published in June by Allen Lane, The Penguin Press (£12.99)
D J Taylor's biography of George Orwell will be published next year