CHURCHILL: THE END OF GLORY John Charmley Harcourt Brace & Co. ! 742 pages. $34.95 As a historian whose prose was as grandiloquent as his oratory, Winston Churchill was confident of his place in history. History would be kind, he liked to say, "because we are writing it." But the author of so many memorable passages -- including the paean to his generation's "finest hour" -- hadn't bargained on the corrosive salt of revisionism. From a high perch on Olympus, the great statesman's reputation has declined some over the years, as revisionist scholars have chipped away at the cracks and flaws in the iconography. Now with John Charmley's political biography, "Churchill: The End of Glory," comes a jackhammer assault that seeks to remove the former British prime minister from his pedestal and the pantheon altogether. Mr. Charmley is a young British historian with an acerbic but engaging style. He begins with the premise that if World War II represented a "victory," it was a triumph for the Americans and the Soviets, but not the British. Churchill (1874-1965) had spent most of his illustrious if checkered career lamenting the decline of British power and was determined not to preside over the demise of the empire, but Mr. Charmley says he did precisely that: "In the summer of 1940 Churchill's vision and the ghost of Britain's faded grandeur met for one last moment of glory; after that the twilight fell." The author implies that the twilight might have been somehow averted if Churchill had been able to control his deep-seated "aggressive instincts," stubbornness and ambition. A less headstrong statesman might have recognized that Soviet communism in the long run would pose the greater danger to British in terests than Nazi Germany, and that the Americans were too fickle and ambitious themselves to be counted as a reliable ally. Indeed, the disgraced Neville Chamberlain, who preceded Churchill as prime minister, emerges in Mr. Charmley's estimate as the more insightful and able leader, for discerning the limits of British influence and pursuing a cautious balance-of-power strategy whose realism was mistaken for appeasement. "Chamberlain was planning for the future, Churchill for Armageddon," the author declares. Of Churchill's oratory, Mr. Charmley asks: "The heart was uplifted -- but was the mind eclipsed?" Hitler was stopped, but Mr. Charmley concludes that "Churchill had been forced to bankrupt Britain and to mortgage her future )) to the United States -- and in the process, he had helped raise the spectre of a menage which was even greater than the one he had destroyed, if only because there was now no balance of terror on the Continent." Mr. Charmley criticizes Churchill's "dicey" assumptions about the intentions of Russian leader Josef Stalin and U.S. President Franklin Roosevelt. But could any assumptions be dicier than the author's (and Chamberlain's) supposition that Hitler's peace feelers in 1940 could be trusted? Even if Churchill had "swapped appeasement of Germany for appeasement of America and vTC Russia," by any rational -- much less moral -- measure, was not such a choice the lesser of two evils? And whatever the outcome in 1945, was not the twilight of the British empire foreordained by events earlier in the century? The biographer writes at one point: "It was difficult to see what, the defeat of Germany apart, the British could hope to gain from the war." But what else truly mattered? Content to demythologize Churchill without completely discrediting him, Mr. Charmley alternates between irreverence and grudging respect, conceding the former prime minister's courage, charisma and indefatigability even as he questions his judgment. Churchill's admirers grant that his heroic qualities often competed with a darker side of excess and eccentricity. Whereas the lionizers -- most notably William Manchester -- have excused his faults and occasional spectacular blunders as the product of a bold spirit and prodigious energy. Mr. Charmley is not so forgiving. The fits of temper, the legendary impatience, the irregular sleeping habits, the self-absorption that dissolved into arrogance and conceit -- where the prime minister's champions viewed these as mere peccadilloes, the interesting edges of a brilliant and complex man, Mr. Charmley characterizes them as symptoms of a fatally flawed and self-destructive nature. Mr. Charmley belongs to the genteel school of character assassination, relying on gossipy asides to damn his subject with faint praise or wrapping a mordant put-down in a pleasing aphorism. Referring to Churchill's brimming self-confidence as a young army officer, he observes: "Ambition and youth, like the ankles of a lady, were likely to arouse passions unless decorously concealed." Churchill's son, Randolph, who was "handsome as a Greek god and twice as arrogant," "never worked to acquire the authority without which fluency becomes glibness." The sarcasm becomes tiresome in spots, the turns of phrase sometimes too cute, but the persevering reader will be rewarded with wonderfully vivid lines, as when Mr. Charmley has Churchill "stalking through the bombsites with taurine glares of defiance, massive cigar stuck firmly in his mouth." "The End of Glory" offers other dividends. Even in its worst moments the book is no mere hatchet job, and at its best it is a work of impressive research, skill and scope. In 700-plus pages covering over a half-century, Mr. Charmley deftly traces a mercurially shifting British political scene and Churchill's own fitful evolution from Victorian subaltern to cold warrior. Although the 1939-1945 period dominates the account, some of the earlier chapters are surer and more astute. If there is a troubling aspect to this provocative volume, even more than the strained premise, it is the too-casual citation of the work of Nazi apologist David Irving and the insertion of several gratuitous references to Churchill's "Jewish friends" and "Zionist bankrollers." It is unfair to insinuate, as some reviewers have, that such indiscretions betray a pro-German sympathy or, worse, an underlying anti-Semitism. But their presence contributes to the impression of both a moral and intellectual shallowness that undermines what, given the length and breadth of the subject, might have been a more compelling reassessment. In calling attention to the author's warts rather than those of his subject, they, along with the book's other shortcomings, leave Sir Winston's stature still secure and his pedestal only slightly rearranged. Mr. Rochester, a historian with the Department of Defense, has written two books on American history.