In one of France's worst moments, World War I hero Philippe Petain shook hands with German dictator Adolph Hitler on Oct. 24, 1940.
Addressing the French nation a few days later, Marshal Petain exclaimed "I enter today down the road of collaboration."
Petain, who had witnessed the surrender of Germany to end World War I, was chosen by Hitler's Nazi regime to lead France's puppet Vichy government, which ostensibly ruled a part of France not occupied by the Germans.
After Hitler's downfall and the end of World War II, liberated France under the leadership of Charles de Gaulle tried the 89-year-old Petain and other Vichy collaborators on charges of treason.
British historian Julian Jackson's critically acclaimed "France on Trial: The Case of Marshal Petain" examines the trial, in which Petain was sentenced to death. De Gaulle, his former close friend, commuted the sentence to life imprisonment, and Petain was held prisoner on a small island, where he died in 1951.
As the title indicates, Jackson's book explores how Petain's collaboration with Germany implicated the entire country. After the war's end, France's resistance movement began a wave of harsh punishment for collaborators, including killings.
Petain claimed that he was a "shield" for France, saving it from the more extreme Nazi occupation suffered by Poland and other countries.
The Vichy regime repealed France's liberal laws, restoring a pro-Catholic conservatism. France's right-wing political groups until recently extolled Petain as a national hero.
Under Petain, French Jewish citizens were captured and sent to Nazi camps, although at a lower percentage than in other countries, likely because of the success of the resistance movement in protecting Jews. Jackson documents that the Vichy government independently acted against Jewish citizens as much as from German coercion.
Jackson has written a series of definitive histories of France's World War II experience and its aftermath, including a highly praised biography of de Gaulle ,who led France after World War II and returned to power as head of the Fifth Republic from the late 1950s through 1969.
"France on Trial," published by Harvard University Press in August, is a major work that holds deep lessons for the United States and its imperiled democracy.