THOMAS E. DEWEY is likely to be remembered in American political history as something more than just another "also ran" largely because of a memorable photo, the one of a triumphant Harry Truman holding aloft page one of the Chicago Tribune with its anticipatory headline "Dewey Defeats Truman."

But it may well be that Dewey's true legacy to his nation arises from neither his 1948 loss to Truman nor his defeat four years earlier by "the champ," President Franklin D. Roosevelt, but rather from his important role in propelling Richard M. Nixon into the vice-presidential slot at the 1952 Republican convention.

This is an exhaustive, well-researched and well-written biography about a young man in a hurry from Owosso, Michigan, who became, in New York City, the nation's hard-charging preeminent gangbuster, U.S. District Attorney at 31 and for 12 years a first-rate governor of the Empire State. He gained his footnote in history as the only Republican twice nominated and twice defeated for the presidency. William Jennings Bryan did that three times for the Democrats but Bryan was also important as the precursor of the social reforms of Woodrow Wilson and the two Roosevelts.

An eastern establishment Republican, Tom Dewey was an internationalist who accepted the basic reforms of the New Deal. As such he was roundly disliked, often hated, by the isolationist mossback wing of his party, accused of being a "me- too" candidate against FDR and of having thrown away certain victory over Truman. For more than a decade and at three national conventions Dewey battled Sen. Robert A. Taft, "Mr. Republican," for the soul of their party. Dewey was one of the important enticers of Gen. Dwight D. Eisenhower into the 1952 contest, a hardball strategist in winning the nomination and then a sometime adviser to President Ike (who, like Nixon later, offered Dewey the chief justiceship). It was at the '52 Chicago convention that Sen. Everett McKinley Dirksen, fighting for Taft, shook his accusatory finger down at Dewey sitting in the New York delegation and, in one of those wondrously revealing moments of politics, thundered that "we followed you before and you took us down the path to defeat." Dewey "sat imperturbably, with the faintest trace of a smile pursing his lips" as the hall erupted "in waves of protest and approval."

Richard Norton Smith, currently a speechwriter for Reagan administration officials, was born five years after Dewey's '48 upset. He ably paints the Dewey story against a wide canvas embracing small- town America, the Great Depression, the era of virtually unrestrained gangsters and racketeers, the New Deal and the split in the GOP evident to this day.

Dewey's talents, writes Smith, "were limited by serious flaws, by a temperament too rational for politics, a daunting competence, and an unwillingness to accept the changed rules of a game reinvented" by FDR. "He sought only to set fire to logic. Neither a crusader nor a hero in the conventional sense, he had instincts for thoroughness, order, and expertise. . . . He would undoubtedly have made an abler president than candidate." But how able we shall never know. Walter Lippmann, who disliked Truman, used to argue that Dewey's '48 defeat led the embittered GOP into McCarthyism and other excesses because the party was so long denied the White House.

Five feet eight, with "a stumpy 160 pound physique," Dewey had "a pair of luminous, unrelenting eyes" and "an extraordinary voice" of "resonance and freshness." But many found him vain, "cold as an icicle," "priggish," "crotchety," "high-handed," yet perhaps "more shy than stuffy." Frances, his wife of 42 years, was "an attractive alkali to his acid." He once told a friend that except for him "I am the most goddamned arrogant person in the country." Reporters found Dewey a man "you have to know well to dislike," and one that "struts while sitting." Alice Roosevelt Longworth said he "looks like the little man on the wedding cake" (or rather, as she told me, she repeated that crack made by her dentist). When at 42 Dewey announced for president against FDR, Harold Ickes snapped that he'd "thrown his diaper in the ring."

Dewey had a "prickly distaste for the stunts required of would-be presidents," he "found it 'absolute torture' . . . to plunge into a crowd of strangers and shake their hands." He "elevated his lack of public heartiness to the level of principle."

How did such a man ever get so far so fast, even if not to the White House? He was bright, dogged, honest. As a crimebuster Dewey was "a godlike figure, jealous of his Olympus," writes Smith. One of Dewey's young men was William P. Rogers, later attorney general and secretary of state. He told Smith he got his job by telling Dewey: "Nobody knows me. I come from a small town in New York. If I work for you, then everybody will know me. I'll never have to prove I'm able or honest, because people know you only hire able and honest people."

And so he did. Enthralling are the parts of this book that detail Dewey's relentless pursuit of such figures as Lucky Luciano, Dutch Schultz, Jimmy Hines, Waxey Gordon, Louis "Lepke" Buchalter and Richard Whitney. His governorship, coming after that of Al Smith, FDR and Herbert Lehman, was a model of GOP fiscal progressivism (he would later view Nelson Rockerfeller as a fiscal wastrel). William Allen White, back in 1939, aptly described Dewey as "a prosecutor" who "is arranging facts for the jury and not for the truth . . . truth as truth has not yet come into his interest so much as the arrangement of the facts to prove a case." Dewey never really changed.

There are fascinating vignettes of Lowell Thomas who trained Dewey's political voice and sold him his Pawling farm; of Wendell Willkie who pushed aside both Dewey and Taft to win the 1940 nomination; of law school classmate William O. Douglas who gave him a critical early boost; of Thomas G. Corcoran who interceded most unjudiciously with Judge Ferdinand Pecora who was hearing a Dewey case; of Hubert Humphrey who became a friend; of Lyndon Johnson who shared Dewey's dislike of Robert Kennedy and whom Dewey advised that the JFK film at the 1964 convention be shown after, not before, the vice presidential nomination lest Bobby "stampede" the delegates; and of how the first political action committee (PAC) sprang from the CIO's fear of Dewey in 1944.

Dewey first heard Richard Nixon speak in early 1952 at a New York fund-raising dinner. "That was a terrific speech" he told the senator, inviting him to his suite where, as Nixon has acknowledged, he first heard of his possible selection as a vice- presidential candidate. Dewey considered Nixon "good, intelligent, middle of the road" with "a very fine voting record," "a fine record in the war"; "most of all," he said later, "he was an extraordinarily intelligent man, fine balance and character." By the time of Ike's nomination, Dewey, Gen. Lucius Clay and Herbert Brownell (a Dewey legacy to Ike, as was Jim Hagerty) had agreed on Nixon. So, when two dozen GOP leaders met to pick the man for Ike, Dewey asked "What about Nixon?" outlining his advantages, one of which was his reputation as a Communist fighter gained in the Hiss-Chambers case.

Later, when Nixon was in danger of being thrown off the ticket because of his secret "fund," it was Dewey who gave Nixon the crucial advice: go on television and ask listeners to wire their verdict to the candidate. Nixon wisely directed the flood to the GOP national committee. Though some aspects of Dewey's subsequent role remain hazy, Smith concludes that in the end "Dewey had rallied to Nixon's side, albeit with undeniable misgivHe ings." He never lived to see Nixon's disgrace.

Richard Norton Smith's hefty biography exudes that human warmth so critical to the successful politician yet so lacking in Tom Dewey. Failure, as well as success, can instruct and illuminate.