Maybe he was even cleverer than he was sweet

Everyone has his or her favourite Jimmy Stewart picture - but we all shared in everyone else's too. He had been to Princeton, but he smacked of small towns on the prairies. There was so much of him to go around, and such a collective affection for the tall, wide-eyed, hesitant, idealistic and innately lovable young man, with that drawling, let's-work- it-out-as-we-go-along voice, the aching flex of romantic and liberal indecision - it was a voice Stewart was doing long before all the impersonators in the business found him as their fail-safe act. Later in life, in relaxed talk shows, when he could put words and thoughts together as well as or better than most people, Stewart was capable of "doing" himself, of going tongue-tied and well, golly, now - as if a rabbit in his mind kept interrupting him. In other words, "Jimmy" Stewart was a sweet guy and a very clever actor. And don't be taken aback if, one day, some book comes out to tell us he might even have been cleverer than he was sweet.

Judge him, as he asked, on the pictures, and the imaginary guy Harvey talked to: remember the shy way he eyed and mastered Dietrich in Destry Rides Again; dwell upon those exquisite scenes he had with Margaret Sullavan as misunderstanding lovers in Shop Around The Corner; I think of the awe and the growing sense of life with which his journalist realised that he might be noticed, and liked, by Katharine Hepburn's Tracy Lord, and then recollect the tact with which he let her off the hook of being sloshed one night. That's The Philadelphia Story, one of the last American movies made for grown-ups and in which he and Cary Grant confronted the difficulties in being gentlemen.

That young Stewart made comedies and romances; he even sang in Born To Dance - it was a high, higher voice, close to the sound range that only bats and women in love can hear. That Stewart was fit to be a great lover, no matter that he didn't entirely look the part. Women in the audience were wild about him, and in life there were reports that he knew more than his screen face suggested (he did not marry until he was 41, yet he did research). But there was no sham to the innocence in that utterly American classic, Mr Smith Goes To Washington, where he played the decent Everyman who believes he may re-animate the nobility of the American political process. Maybe Gary Cooper could have played Smith - he'd come close a few years before as Frank Capra's Mr Deeds. But Mr Smith has to talk; he has that crazed filibuster to keep the Senate from its drab, corrupt ways. Stewart could go to the end of his tether in that cause - hoarse, weeping, fainting - but he never exaggerated the faith in Smith, or the ordinariness of the man. He played the part like Tom Joad turned into the young Sinatra in a marathon song contest. He was the poet and the unknown American, lyrical and not far from fascist.

Stewart had a real war - unlike most Hollywood actors who put on uniform and did morale-boosting photo ops. He flew bombers over Germany - 20 missions - and rose from private to colonel. Like many film-makers who went overseas (usually directors, like Capra, Huston and George Stevens), Stewart was more than just a few years older in 1945. He had been marked by the experience, the suffering and the discovery that golden-age Hollywood had known so little about the world. That enforced maturity had a great deal to do with the haunting darkness of Capra's It's A Wonderful Life, the movie that sees so many perils and pitfalls in the American pursuit of happiness. It is hard to think of another actor who could have made the small-town champion, the family model and the near-suicidal parts of one person.

There were a few other famously gentle roles at this time which - allied with George Bailey in It's A Wonderful Life - secured his place in hearts of the world. The most notable of these were No Highway, in which he played an absent-minded scientist, Harvey, in which he communed with a rabbit, and The Greatest Show On Earth, where he did the whole film under a clown's make-up - holding us with that voice.

But then, just as he had fused with Frank Capra in the 1930s and 1940s, so Stewart fell in with two new directors who would find a rather different inner man: Anthony Mann and Alfred Hitchcock. Mann made westerns, and he liked heroes who were trying to conceal flaws, anger or a need for revenge. In the 1950s, the two men combined on films that have not dated or slackened as ambiguous moral tales: Winchester 73; Bend of the River; The Naked Spur; The Far Country; The Man From Laramie. In a uniquely peaked and battered Stetson, invariably having to balance selfishness and community values, Stewart was an ideal hero in an age when heroism was losing its confidence. There was another novelty in those films: Stewart and his agent, Lew Wassermann, had secured a pioneering deal that gave the actor a portion of the profits as well as an up-front fee. And you could believe that the Stewart of these films was that tough and shrewd a negotiator.

Hitchcock made his greatest films in the 1950s, and maybe the best of them are Rear Window and Vertigo, in which Stewart is the hero and the protagonist, but a strangely enclosed, neurotic figure too. In Rear Window, he was the voyeur photographer, laid up by an accident, seeing and breathing the spirit of murder into the courtyard of windows he watches. Grey-haired now, and a little colder in his gaze, Stewart was an obsessive, a man who might sacrifice others to his intense, hard vision. Rear Window ends well enough, with the voyeur vindicated, but in Vertigo he is the private eye whose private dream turns to pathology. He is a decent enough figure at first sight (though there are hints at his failures in real relationships), but he is also an odd mix of sadism and masochism, a selfish manipulator of others (a director?), and the self-pitying victim of his own morbid romanticism. Vertigo and Rear Window are among the great American films, and alarming portraits of self-sufficiency gone wrong. It is to Stewart's huge credit that he did them while he was reproducing his charm in The Glenn Miller Story and Bell, Book and Candle. Not every actor would have risked dismantling his old image with the remorseless enquiry of Vertigo. He was nominated for neither Hitchcock film, though he did get best actor Oscar nominations for Mr Smith Goes to Washington, The Philadelphia Story (his one victory), It's A Wonderful Life, Harvey and Otto Preminger's Anatomy of a Murder, one of his most enjoyable pictures, in which he plays a country lawyer who trades on homespun virtues.

Stewart made a few films for John Ford in the early 1960s - Two Rode Together, far too old as the naive lawyer in The Man Who Shot Liberty Valance, and a pastiche of Wyatt Earp in Cheyenne Autumn. Thereafter, he settled for poor material and unworthy films, though he was very good as the doctor who tells John Wayne he is dying in The Shootist. He was retired by the early 1980s, and in the 1990s he was horribly stranded by the death of his wife, Gloria. It was fairly clear that in his last years he looked forward to death.

There is something else to be said beyond noting Stewart's sweet nature on screen, his range and his courage in finding a darker character than the one that had made him endearing. It has to do with the fact of his dying just one day after Robert Mitchum. Mitchum had been a movie star since only the 1940s; Stewart had an authentic career in the 1930s, in what we think of as the true golden age. With two great losses in a week, we have to recognize how few are left from the 30s - Loretta Young, Bob Hope, Katharine Hepburn After that, the screen will be the only way of remembering. The golden age is no longer our age; we cannot claim its riches as our own. "Hollywood" begins to fade back into the mythology that includes fin-de-siecle Paris; Augustan England; the Dark Ages, and so on. And that is a way of saying that there will never be movie stars again as once there were. That's not just because they don't make them that way any more. It's rather more because we have grown out of the sweet innocence that believed in them. We are sadder, wiser, and more haunted now - like Stewart at the end of Vertigo, that supreme parable about the age of movies. For our sanity and our culture that may be a good thing. We may be better off in doubt, without graven images. But Jimmy Stewart may have been the last man we all loved - and the hell with the evidence. After all, loving strangers may be the last vestige of religion.