I GREW UP with an heroic picture of the Abraham Lincoln Brigade. They were the brave young men of the '30s, the legend went, who went to Spain and fought the "good fight" in the Spanish Civil War, defending democracy against the burgeoning threat of fascism. They were the flower of the American left, "premature anti-fascists," who alone sought to rouse the world's conscience about the destruction of the Spanish republic.

Old legends die hard. But for me, after sifting through the historical record of what actually happened in Spain 50 years ago, the old romantic picture has been shattered. The story of the Lincoln vets, rather than being a tale of heroism and virtue, is a story of how good people were manipulated by the Soviet Union for its own ends.

I began with a romantic view of the Lincoln Brigade because my own uncle, Irving Keith (nee Kreichman, but like so many young Jewish Communists he took a new name to more "Americanize" himself) went into battle near the end of the Spanish republic's collapse.

"I'm really anxious to meet your son," he wrote my father in one of his letters home from Spain, "but that will have to wait until the war is won."

I was never to meet him. Appointed a "commissar" by the Brigade, he was killed in battle during the 1938 spring retreat. My family honored his memory, and I grew up filled with the lore of the Brigade. Like the actor Richard Dreyfuss, who spoke at one of the vets' recent reunions, I, too, considered them authentic American heroes.

Spain was the radical chic cause of the 1930s. It was, as Murray Kempton wrote, "the passion of that small segment of my generation which felt a personal commitment to the revolution." The eminent sociologist Lewis Coser recently reflected in Dissent that for his generation of the European left, 1936 was a "watershed," a period in which all seemed open and possible. "The occupation of the factories by millions of French workers in June 1936 and the outbreak of the Spanish Civil War . . . seemed once and for all to break the despair that had settled on those of us who considered themselves Marxists."

Coser remembers looking on with amazement at what he calls "an almost instinctive reaction of the working class," who disarmed police and civil guards. Worker militiamen took over luxury restaurants and opened them to the populace; luxury hotels became headquarters for revolutionary organizations. It was, as George Orwell wrote in "Homage to Catalonia," "a sort of microcosm of a classless society . . . a crude forecast of what the opening stages of socialism might be like." It was, he confessed, a vision that "deeply attracted me."

That vision has been romanticized and distorted in the years since, particularly made to fit the analysis and line of the Communists. It is a potent myth, that of a generation of idealistically motivated young people spontaneously joining the fight against fascism. At a time when the rest of the world ignored the threat, these premature anti-fascists rose to the occasion, committing their bodies and even their lives to the fight.

It was the one pure cause of the 1930s: a legally elected democratic government battling against reactionary generals who wanted to install a Spanish version of fascism. The democratic republic was alone and embattled: the western democracies stayed neutral and would not sell it arms, while the fascist regimes in Germany and Italy rushed men and weapons to aid General Franco's rebellion. Defense of Spain was the symbol for all that was good and decent organizing against the tides of reaction and Nazism.

For the Lincoln vets, this history became a catechism. Only Soviet Russia came to democratic Spain's aid, the Brigade fighters claimed, and the Soviets proved by this action that they were on the side of the people. It was Russia, they concluded, that gave light and hope to the oppressed of the world. Between the Lincoln Brigade soldier and his enemies stood his rifle, supplied by Russia. The aircraft, tanks and artillery protecting him all were of Soviet origin. The admiration of the volunteers for the Soviet Union was boundless.

Spain became the central metaphor for artists, intellectuals and writers of the 1930s. Hemingway immortalized the conflict in "For Whom The Bell Tolls," although the veterans were piqued at his critical portrayal of French Commissar Andre Marty. When they issued an anthology of writings from Spain in the 1960s, they still could not see fit to include any excerpts from Hemingway. W.H. Auden immortalized the conflict in his poem "Spain, 1937," the call to arms being heard on the "sleepy plains" and the "corrupt cities."

"Madrid is the heart," Auden put it -- of a world, a civilization and an ideal. British poet Stephen Spender edited an anthology of veterans' writings, and Hemingway narrated the fund-raising film by Joris Ivens, "To Die in Madrid." Two generations later, in the 1960s, this film enjoyed a robust run in art movie theaters around the country.

The hagiography continues. A documentary film, "The Good Fight," received wide distribution two years ago, and a new oral history of the vets, "The Premature Anti-Fascists," further romanticizes their story. And this week a gala event is taking place at Lincoln Center in New York. The veterans of the Abraham Lincoln Brigade are celebrating their 50th Anniversary with a script by Ring Lardner Jr., and a concert by The Weavers, who will again sing the stirring songs once heard on the battlefields of republican Spain.

I, too, once shared that thoroughly romantic image. In fact, the myth of Spain persisted for me even after I wrote a book debunking another of the celebrated causes of the Old Left, the Rosenberg case. My book "The Rosenberg File" documented that Julius Rosenberg had engaged in espionage for the Soviet Union. This conclusion enraged the Old Left; no amount of interpretation of factual data could convince them to shed the version of history to which they were wedded. But even after this experience with Leftist mythology, I somehow thought the Spanish Civil War was a different case -- an exception to the rule.

I was again proven wrong. What I found when I investigated wasn't the story of a heroic generation fighting against fascism, but a lesson in how the idealism of a generation was used, manipulated and ultimately betrayed in the interests of those who had at heart a cynical realpolitik.

The story of the Lincoln vets cannot be taken out of the context of communism. The blind spots revealed by the Lincolns were those of their comrades in the communist movement. Oblivious to Stalin's purge trials, which were contemporaneous with the war in Spain, the brigade members saw Stalin only as the world's hero -- the man whose arms were helping them defend the fledgling Spanish democracy.

The reality of Spanish events did not conform to the image personified in the Comintern's interpretations. The soldiers went to fight for democracy -- but only a few realized that their battalions were put together for a greater purpose in which they served only as pawns: to fashion Spain in the manner desired by Joseph Stalin, who needed to create a situation in Europe that would serve his foreign policy ends.

I began by reading through my uncle's letters, where one can find all the themes and beliefs that lead so many men to battle. His letters are a mixture of moving assurances to his sisters and his mother that there was no need to worry -- he would be home safely when the war against Franco was won. Others were long political dialogues -- attempts to convince his family that the communist "Popular Front" policy was correct.

"The main political problem," he wrote, "is that of strengthening the unity of the working class." By that he meant the need to get the anarchists and socialist "irresponsibles" to join with the communists in support of the moderate goal of defending the bourgeois republic. Worse were those in the "rearguard" who opposed communist policy and sought to "create divisions in the Popular Front." Clearly, he was alluding to those hated "Trotyskites" who thought the fight was about consolidating a revolution.

Ever optimistic, my uncle described the bitter defeat suffered by the loss of Teruel in 1937 as a victory, since the Loyalists took the city in only six days, but lost it to Franco after two months of bitter fighting. "One is deeply impressed," he wrote, "by the heroism, determination and spirit of the people in the face of all their difficulties and sacrifice." Through the years the same has been said of these men of the Lincoln battalion.

No one can doubt the heroism and bravery of men like my uncle, but so many decades later, one cannot avoid noticing their total naivete -- all good was on one side, all evil on the other. But was Spain and the Civil War a simple good fight on behalf of democracy against fascist tyranny? If Murray Kempton was correct in his much-quoted observation that it "was a canon of the myth of the '30s that these were all heroes who died with their faces to the enemy," new evidence and analysis shows that Kempton's iconoclasm was misplaced in debunking "the myth of the '50s that most of them fought . . . for a cause betrayed by the Soviets." That, in fact, is precisely what did happen.

The truth is that Stalin got involved late in the war, via a policy of cautious military intervention. Soviet tanks, planes and artillery did not reach Spain until October and November of 1936, and they were of a limited caliber -- no match for the heavy equipment supplied by the Germans and Italians. Even so, the Soviets received payment in advance, by taking the valued gold reserves of Spain to Russia. Fearing involvement in a war with Germany and Italy, Russia limited its aid to bolstering the resistance of the anti-Franco forces until such time as Britain and France might be induced to abandon their policy of non-intervention.

Stalin's cyncical goal was to steer internal events in Spain to coincide with his foreign policy objectives. He wanted to prolong the existence of the Spanish republic until the western democracies joined him in supporting the republicans. It was a stalemate strategy; Stalin never gave the Spaniards enough arms to win. The ill-equipped Brigade troops were sitting ducks -- led off, as one American commissar put it, as "sheeps to the slaughter."

Alongside Stalin's military advisors came his intelligence and political operatives, who managed to dominate the republic by 1937. The quid pro quo for Soviet aid was the push to purge and liquidate those on the left who did not accept Stalin's views. Spanish communists in particular executed Kremlin directives without hesitation, although, as Burnett Bolloten, author of "The Spanish Revolution," puts it, "those directives meant antagonizing other parties of the left and eventually undermining the war effort and the will to fight."

The reign of terror inflicted on republican Spain by Stalin's agents was described by Gen. Walter Krivitsky, one of the first Soviet defectors to the United States. Krivitsky had been head of both Soviet military intelligence in western Europe and the the Soviet secret police in Spain. His revelations to congressional committees and the press after his defection led to an international Communist campaign to smear Krivitsky as an untrustworthy witness in league with the Nazis.

Krivitsky explained the details of how Stalin's agents operated in the Spanish republic. What they brought to Spain was an unmitigated repression and terror -- the civil war against the Spanish left, a war within the civil war. The regular police corps was reorganized. Communists secured the pivotal positions in the newly-rebuilt police, which became a formal part of the Soviet apparatus in Spain. The Soviet intelligence service, the NKVD, Krivitsky wrote, "had its own special prisons. Its units carried out assassinations and kidnappings, filled hidden dungeons and made flying raids. It functioned . . .independently of the Loyalist government. . . . The Soviet Union seemed to have a grip on Loyalist Spain, as if it were already a Soviet possession."

Members of the Lincoln Brigade had to know about some of the terror. They had undoubtedly heard about the murders carried out by the French communist brigade leader Andre Marty. By his own account, Marty had some 500 of his own men shot for desertion, or for the political heresy of "Trotskyism." In other words, one-tenth of all the volunteers killed in the civil war were shot by Marty, and his own figure is seen as modest by many who worked with him. Many of the volunteers came to call Marty "the butcher of Albacete," after the training camp over which he presided. So much had Franco and the communists acted the same, that one leading anarchist aptly commented, "whether Premier Negrin won with his communist cohorts, or Franco won with his Italians and Germans, the results would be the same for us."

The Lincoln vets are right about one thing. The western democracies disguised their inactivity and tolerance of fascist aid to Franco as "nonintervention," leaving the Spanish republic defenseless and making it easier for the Soviets to achieve their aims. Spain became a pawn in a chess game of the world's big powers.

The veterans should listen to one of their own, John Gates. Gates was the revered 23-year-old commissar of the XV Brigade 50 years ago, and he was promoted to chief American commissar after 1937. Later an editor of the Daily Worker, Gates quit the American Communist Party in 1958. Now, years later, Gates stays aloof from the official Lincoln veterans organization, which he considers to be too close to the communist view of events. The Lincoln volunteers, he says, "fought with the best of intentions, they held noble ideals, but they fought in a system controlled and run by the Russian Communist leadership, then under the control of Stalin." The result of their effort, Gates puts it, was to "insist on adherence to the policy advocated by the Spanish communists, which at first helped but later hurt the ability to wage an effective war, hindering what support we could get in Spain."

It is an ambiguous judgment of the role they played. Most of the Lincoln Vets prefer to only celebrate. But history is more attuned to shades of grey than to black and white.

My uncle's last note was written "as I ride in a very jerky, bouncing box-car which seems to have square wheels," on the way to the front after five months in a training camp. "I'm happier," that young man wrote, "than I've ever been."

I have no doubt that he was and that he died believing he was fighting the good fight. But looking at the weight of the historical evidence today, I can only conclude that his death was in vain. By the time he went into battle, the Comintern had already decided that Spain was expendable. Unity with Britain and France was more important, and the theatre of operations was turning to Europe. Men were sent into a battle that could not be won for the reason of propaganda alone. Stalin was even beginning to explore mending fences with Hitler, and was soon to order the recalling of the Brigades. If my uncle had stayed on base, he would have still been alive. He went to his death defending a democracy that had already been defeated by the inaction of the West and the cruel realpolitik of the Soviets.