BENEDICT ARNOLD'S classical treason and Aaron Burr's sinister plotting are as integral a part of American tradition as Nathan Hale's martyrdom or Benjamin Franklin's diplomacy. Arnold and Burr are the flip side of the historical coin, and to try to turn either into a hero seems a thankless task.

Gore Vidal can leave Benedict Arnold alone, but he can not restrain himself from trying to polish the tarnished reputation of his maternal ancestor Burr. He does not try to turn Burr into a hero, but he does attempt to make him into something less two dimensional than the flip side of a coin. For this day and age, Vidal's attempt constitutes a rehabilitation of Burr. No one tries to write Parson Weems-type historical fiction anymore: larger-than-life heroes like Washington are no longer very appealing. To turn a villian into a hero of today's world-historical audience, the modern technique involves showing the basic humanity of the culprit while simultaneously debunking the old heroes. So Vidal's Burr endlessly derides Jefferson for his hypocritical dishonesty, Washington for his sanctimonious self-righteousness, Hamilton for his arrogant aristocratic-leanings. And this Burr is a man of his times--intoxicated by the Napoleonic vision of his era, but hardly to be faulted for being a product of his period.

If there is any point in rehabilitating Burr this book does not make it, but since Burr is a historical novel rather than a learned defense of an ex-vice president of the United States, its failure in interpreting the period is incidental. Burr remains what he was--Revolutionary War hero, New York lawyer, vice president, Alexander Hamilton's murderer, Western adventurer, exile, and New York lawyer again. Burr concentrates on the public events in Burr's life--making numerous and obligatory bows toward his home life, but never really exploring it with the exception of one grotesque incident late in Burr's life, his brief marriage to a rich old whore.

BURR WAS ONE of the most intriguing early American politicians. Vidal takes the material at hand and succeeds in turning out a coherent, internally consistent narrative. He does so using an almost disjointed technique--developing the story of Burr's career simultaneously through "memoirs" attributed to Burr and through "research" supposedly conducted by Charles Schuyler, a young journalist and friend of Burr.

The disjointed narrative has its advantages. Schuyler's research is used to fill in Burr's background, to reveal little tidbits of bastardy that Burr could not plausibly put in his memoirs. More importantly, by purporting to include portions of Burr's own memoirs, Vidal can ascribe motives to Burr's activities throughout the man's public career.

Vidal claims to find this freedom to ascribe motives very important, so important that it is itself responsible for his chosing to write a historical novel rather than a history. In an After-word he maintains that the novelist can ascribe motives to historical figures such as Burr, while historians, insofar as they are scrupulous, must refrain from doing so.

By imputing motives to Burr, Vidal hopes to penetrate his subject's mind and explain his behavior. As a novelist, dealing with history, Vidal sacrifices his ability to manufacture situations, but he is free from the strictures binding historians. This may explain the limits facing the historical novelist, but it does little to indicate the benefits a novelist derives from subjecting himself to the constraints of an historical situation. The motives conjured up by the novelist have no source from which to derive validity; they are only the imaginings of a modern writer.

VIDAL HAS WRITTEN another historical novel, Julian, set in much different circumstances. It is the story of Julian the Apostate, a late Roman Emperor, and the novel stands in the Walter Pater tradition. But in Julian Vidal did more than merely ascribe motives to an historical actor--he developed the actor into a rather remarkable character. Burr remains an historical figure, with attributed motives, but little real depth.

Which is not to say that Burr is a bad book. It is an enjoyable book. Historical novels are probably never capable of being great, they are rather like muzak in that respect. They can be very bad, or they can be soothing and even good, but the chances of encountering a great historical novel or a memorable bit of muzak are very slim.

Instead, historical novels tend to entertain, distract, and pander to escapist tendencies. Certainly Vidal is a good enough writer to produce generally competent work, and when Vidal chooses to write an historical novel, he is likely to write a good one. But there is no reason to expect him to transcend the boundaries of the field, and he has not.