BOOK REVIEW / A tricky way with whitewash: Nixon: A Life - Jonathan Aitken: Weidenfeld, pounds 25

WRITING and publishing political biography is a little like being a weatherman. The trick is to predict changes in the national temperature. Recent adepts in the art of reputation-meteorology include John Charmley - who guessed that there was now sufficient distance from the Second World War and from the official Martin Gilbert biography for revisionism on Winston Churchill - and Ben Pimlott, whose defence of Harold Wilson, Britain's last elected Labour Prime Minister, benefited from appearing during a period of extreme Tory disorder. Now, God help us, comes Richard Nixon: The Justification. This biography, too, is calculated on the possibility of sunshine for its subject, and some reviewers have enthusiastically seen the light. This reader, however, remains reluctant to chuck away the umbrella.

It may be no coincidence that the author attempting this ambitious makeover is a contemporary Conservative minister. The chance in the market for such a volume is surely connected with the concept of non-accountability and Teflon politics which has developed among the parties of the Right in Britain and America during the last 10 years. If Reagan and Bush courted impeachment and survived, then the only American president ever to resign can be made to seem a figure of antique honour. It is this task which Aitken undertakes, in a volume which suggests that Nixon was wrong to leave office voluntarily and was forced out by a liberal conspiracy.

Part of Aitken's motivation is political. Nixon's judicial elevations were, the biographer insists, a 'much needed correction of the Supreme Court's tendency towards overt political liberalism'. Coincidence of ideology is common enough in political biographies, but Aitken suffers the dangerous complication of personal acquaintance. The biographer and his wife honeymooned at the ex-president's California house, a courtesy extended because of Aitken's organisation of Nixon tours to Britain during the messy political exiles which bracketed Nixon's presidency.

This involvement blesses the biography with fine eyewitness exclusives, of which the best is an eerie scene of ex-prime minister Wilson and ex-president Nixon singing a Gilbert and Sullivan duet during a private dinner at the Dorchester. But when anecdote gives way to assessment, the same access - Nixon granted Aitken voluminous interviews - curses the work with the nervousness of gratitude. In his encouragement of this biography, Tricky Dicky has turned another trick. It is rather as if the biographer fears the subject has his office bugged.

And it is in his handling of Watergate that Aitken's recanting is at its most masterly. The lengthy gap on a crucial Watergate tape was, Aitken argues, deliberately created by a hostile Nixon aide to make an innocuous conversation sound incriminating. (Even the hagiographic captions at the official Nixon Presidential Library in California dare suggest only accidental erasure.) Faced with a surviving tape of Nixon's answer to his aide John Dean's warning that to buy the silence of the Watergate burglars might cost dollars 1 million - 'We could get that . . . if you need the money, I mean, uh, you could get the money . . . ' - Aitken gamely explains that the president was 'thinking out loud' and that, anyway, the transaction was never carried out.

Essentially, Nixon: A Life follows (with acknowledgment) the line of a recent American book Silent Coup, which presented Nixon as the innocent victim of John Dean's activities, himself implicated only in the cover-up. That Nixon did not know of the squalid attempted theft which initiated the Watergate business is sustainable on the available facts. Yet his immediate keenness on the concealment of the burglary - and his long history, before and after, of obsessive secrecy, eavesdropping and the unethical undermining of rivals - can be seen to make this an almost irrelevant decency. The real Nixon was the real Nixon.

The charge against his subject Aitken ducks is that, whatever his personal complicity, he created a culture in which employees felt tacit approval for dubious actions. For example, Aitken mocks the 1974 Schlesinger Protectorate, under which the then Defense Secretary, fearing a Nixon coup, privately arranged for all requests for troop movements during Nixon's last days to be referred back to him. With the tempering of retrospect, this may indeed seem 'the wildest over-reaction to Watergate', but an alternative view is that the incident illustrates what the president's contemporaries believed him to be capable of.

Aitken's glancing allusions to 'the president's darker impulses' are insufficient acknowledgment of the tendency, throughout his career, for those dealing with Tricky Dicky to reach for the garlic and cross. A story is told, though understandably not by Aitken, of the senior Republican Bob Dole seeing a newspaper photograph of former presidents Ford, Carter and Nixon lined up at a state occasion. Pointing to each in turn, Pole intoned: 'See no evil . . . hear no evil . . . Evil.'

Some of the special pleading in this book - for Nixon's achievements in foreign policy and desegregation of the south - is reasonable. In this respect, the shrewdest assessment of the subject is a 1974 remark made by Caspar Weinberger: 'All that talent, all those flaws,' Weinberger whispered to a colleague during Nixon's final cabinet meeting.

This will do, too, as a summary of Nixon: A Life. Aitken has clear talent as a biographer - once the narrative abandons the routine pieties about childhood and war service for the machinations of politics, there is never a drab passage - but the work has the flaws of semi-authorisation and the writer's iconoclastic political mind. Because of this, he never has his subject taped.