Biographers do better by losers than historians, who hanker after those who make the most history. Biographers are bemused by bewitching personalities, whatever their impact on the world. Alcibiades and Coriolanus were traitors, but Plutarch treats their parallel lives as a study in personality. How is it that two men of such different sensibilities experienced such similar fates?

A modern Plutarch would pair Henri-Philippe Petain and Charles de Gaulle, the villain of Vichy versus the leader of the “Free French.” De Gaulle lacked the support of Roosevelt and Churchill until very late in the war, and, as late as 1942, Roosevelt was sending messages to Petain hoping that he would be in place to piece together postwar France.

Instead, Petain made one political blunder after another. He was the Frenchman who helped carry out Hitler’s infamous racial laws and the transportation of more than 100,000 Jews to concentration camps and certain death. He also sent thousands of Frenchman into forced labor in Nazi Germany.

All this led to his being tried as a traitor after the war and sentenced to death. De Gaulle returned triumphant to liberated Paris in August 1944, acknowledged as the provisional leader of France. He would commute Petain’s sentence to life imprisonment. That Petain had been de Gaulle’s mentor in the 1920s makes it all the more poignant.

Charles Williams does not spare his subject, showing that at every turn Petain squandered opportunities the Allies offered him to redeem the French republic by establishing a government-in-exile. In doing so, Petain would have either deprived de Gaulle of his claim to represent France or forced him to share power. Mr. Williams demonstrates in fascinating detail why this many-titled man had the prestige of an honored monarch, a gravity that no other military man or politician could rival. Even de Gaulle, who believed Petain had betrayed his nation by signing the armistice with Hitler, retained the reverence of a protege as he gloomily read reports of the dubious judicial proceedings that condemned his rival for power.

Mr. Williams ranks Petain, the military leader, only a cut below Napoleon and Wellington. His ascent to the role of national icon occurred just as he was on the verge of retirement. Nearly 60 in 1914, he had had a solid, if not illustrious, military career. A peasant boy, he was justly proud of the prowess he had shown as a tactician, and the authority he enjoyed as a charismatic lecturer at military schools. But he was also disappointed in never having achieved the rank of general or broken through the class barriers that barred him from the highest echelons of the French military establishment.

World War I changed all that. Petain learned more quickly than his French and English contemporaries how to fight modern wars. He deplored mass casualties and devised maneuvers that took more effective advantage of modern weapons. Taciturn among his colleagues, he appeared in public the very image of probity, a figure above the machinations of politics. Like the greatest heroes of history (Nelson comes to mind), Petain linked his very life with that of his nation.

At the end of World War I, he carried the baton of a marshal of France and the reputation as the country’s savior in its times of greatest need. He was seen as the man most likely to defend the nation from another German onslaught. It helps to explain why the people turned to Petain, a partisan of no party, a man concerned only with patrie, and why his very claim to stand above politics ensured the doom of the man and his land. But Petain, like his country, lost his way in the 1930s – although neither Petain nor his compatriots saw it that way.

Like millions of other Europeans – and Americans as well – he admired leaders like Mussolini, Hitler, and Franco for annihilating the anarchy of postwar Europe by the force of their own will, which each equated with a national spirit. Petain’s mistake – a common one even as late as 1940 – was to suppose that Hitler was no more than an authoritarian figure. Eternal France would survive him. An armistice bought the French time to regroup; it prevented Hitler from occupying the entire country, and it would give Petain (so he thought) much more leverage by saving his country from total defeat.

Petain thought the French would live to fight another day. But day by day the Nazi regime implicated Petain more deeply in fascist war aims that led to the Holocaust. Petain, fearing for his life and that of his nation, refused to leave France. Mr. Williams does not say it, but to have done so would have meant becoming another de Gaulle, another recalcitrant Frenchman and one too many for the Allies. The irony, it seems to me, is that had Petain left (and Mr. Williams implies he should have), he would have destroyed the very idea that he was France.

Petain is a more tragic figure than Mr. Williams makes out – not merely a senile old man snared in a Nazi trap but a man whose own principles betrayed him. The Plutarchian biographer cannot ignore the parallel: The Vichy regime condemned de Gaulle as a traitor for leaving his country; Petain could not leave France without becoming a traitor to himself.

crollyson@nysun.com