Once upon a time, there was a Labour leader who lost. He had one chance to win an election, and he lost. In private, this leader was warm and witty, a man of culture and integrity. In public, he was a windbag with a shaky grasp of policy. TV interviewers tripped him up. Shadow cabinet colleagues put him down. Rumour had it that he wasn’t up to the job.

Staff in the leader’s private office shielded, chivvied and cosseted him. They lived in a state of perpetual vigilance, poised to preempt potential gaffes. The man who should have been his party’s greatest asset was treated as its greatest liability.

Old hands have rushed to condemn The Absence of War, David Hare’s portrayal of a panicky Labour election campaign. They might pause to consider the implied compliment when a writer accords Labour the status of a great British institution. The Absence of War completes a trilogy that brackets Her Majesty’s loyal opposition with the Church of England (Racing Demon) and the criminal justice system (Murmuring Judges). Eminent stablemates for an upstart that did not see the light of day until 1906.

Besides, here is none of the viciousness and chauvinism depicted in recent dramas of the left (see Alan Bleasdale’s GBH, or the recent BBC2 series Love and Reason). Hare’s apparatchiks are well-intentioned people who have lost the courage of their convictions. Power can only be won, they believe, with a manifesto and a leader as bland as processed cheese. But the pungent reality they have to work with is George Jones (John Thaw, discarding his sardonic Morse manner), an affable south London socialist with a liking for Shakespeare but no Oxbridge degree.

Like Neil Kinnock, like David Hare himself, Jones is a child of the 1940s, and heir to a postwar loss of nerve. The war is a watershed in Hare’s work (most painfully in Plenty). After it comes accidie. The best lack all conviction. The Absence of War starts and ends at the Whitehall Cenotaph, as Jones worries “Could we have done more?”

The Hare trilogy grew out of the author’s belief that: “What’s interesting now is how groups of people live together.” The theatre had seen heroes followed by anti-heroes; it was time to look at institutions. In the 1970s, Hare had written and directed for small, radical companies such as Joint Stock. Now he turned to the vast Olivier stage at the (Royal) National Theatre. The establishment saw itself anatomised as Hare faced down the insistent individualism of the 1980s.

He has acquired a reputation as an earnest moralist—a label that stuck after The Secret Rapture examined the topic of goodness. Yet the trilogy’s comedy quotient is pleasingly high; if this is 19th-century naturalism, it is George Eliot rather than Zola. Racing Demon contains an immortal scene in which clerics go on the razzle, downing tequila sunrises in the Savoy. In Murmuring Judges, a High Court grandee (the marvellous Michael Bryant) describes to a hungry Home Secretary how that evening’s venison will be served—in such detail that the politician’s gastric juices can almost be heard to churn.

Of the three plays, the most ambitious is Murmuring Judges, which shows how courts, prisons and police co-exist in a state of mutual incomprehension. The script sometimes sounds like a research briefing: a detective announces that the average policeman witnesses one crime every ten years, and a QC reminds his junior that three-quarters of all cases come to the barrister the night before trial. The Home Secretary tackles his host on prison overcrowding, citing with approval the German trend towards non-custodial sentences. With Michael Howard in post, these lines sound implausibly liberal.

Murmuring Judges bears witness to Hare’s passion for portraying women as keepers of conscience. An Irish victim of crooked police work is befriended by a black barrister (Alphonsia Emmanuel), while his case also troubles a high-flying young policewoman (Katrina Levon, a disappointing substitute for the original Lesley Sharp). Both rebel against the professional injunction “Don’t get emotionally involved”. You could argue that it is fitting for the whistleblowers to be female: as outsiders, women are better placed to see flaws in the system. But burden an actress with virtue, and she may be reduced to a cipher whose function is to do the right thing.

Racing Demon will hold up better. It is funnier and less schematic: the liberal’s and reformer’s instincts are apportioned to two different characters, and the audience’s sympathy is not so obviously skewed. The tolerant Anglican rector (convincingly played by Oliver Ford Davies) is ineffectual in his inner-city parish; the zealous evangelical (Adam Kotz) is the one who gets things done.

In the wake of these big plays on big canvases, The Absence of War seems oddly limited. Despite huge slide-projections of Westminster, the characters are a small gang in a goldfish bowl. We see little of the shadow cabinet. The trade unions get scarcely a mention. No NEC, no mods and trads: no sense of the wider party. But Richard Eyre’s production bears the stigmata of the 1992 campaign trail. Smart-suited women service their leader with shirts, cigarettes and whisky; ersatz drama erupts in darkened TV studios.

Authentic, yes; engrossing, no. There can never be much suspense about the election result, but the play also lacks the crises of conscience, the moments of revelation or betrayal that electrify parts one and two. In Racing Demon, the curate’s girlfriend (Saskia Wickham) has to watch as his humanity loses out to his faith. In Murmuring Judges, there is the policewoman’s growing suspicion that the detective she looks up to is “bent”.

The Absence of War offers a different kind of dilemma: a battle over how to approach the electorate. Intriguingly, the people who damp Jones’ exuberance are not rose-touting PR men like Peter Mandelson (who came to the first night). They are the leader’s crack troops from his own private office (with Oliver Ford Davies bizarrely cast as a Charles Clarke figure). Jones is kept off topics such as defence or northern Ireland. Frustrated, he wails: “Why can’t I speak of what I believe?”

It is the ad-woman from the outside world (Clare Higgins) who urges the leader to rediscover his real personality. “Be yourself,” she advises. But when Jones tries to address a rally without prepared notes, he breaks down before his audience. He cannot recover his past spontaneous form or remember how to “be himself”. The question is left hanging: would it have worked? Do you offer the electorate what they say they want—or what you think they should have?