André Léon Blum was a French socialist politician and three-time Prime Minister of France. As a Jew, he was heavily influenced by the Dreyfus affair of the late 19th century. Blum was a disciple of socialist leader Jean Jaurès and became his successor after Jaurès' assassination in 1914. Despite Blum's relatively short tenures, his time in office was very influential. As prime minister in the left-wing Popular Front government in 1936–1937, he provided a series of major economic and social reforms. Blum declared neutrality in the Spanish Civil War (1936–1939) to avoid the civil conflict spilling over into France itself. Once out of office in 1938, he denounced the appeasement of Germany.
When Germany defeated France in 1940, Blum became a staunch opponent of Vichy France and was tried (but never judged) by its government on charges of treason. He was imprisoned in the Buchenwald concentration camp and after the war resumed a transitional leadership role in French politics, helping to bring about the French Fourth Republic, until his death in 1950.