From 1919 to 1922, Monnet was deputy secretary-general to the new League of Nations and was instrumental in raising an international loan that facilitated Austrian postwar economic reconstruction. From 1923 until the late 1930s, he was a partner in various American financial firms, raising further international European reconstruction loans in the 1920s and attempting to do the same in China for much of the 1930s.
Monnet was an early opponent of Adolf Hitler, and after the 1938 Munich Agreement, he felt that massive French rearmament and the rapid expansion of his country's air capacity were essential. He represented France in the United States, attempting to facilitate major French purchases of American warplanes. After Britain and France declared war on Germany in September 1939, Monnet was the French member on the joint Allied purchasing commission, which sought to unify Allied overseas war purchases and finance. Before France signed an armistice with Germany in June 1940, Monnet and Brigadier General Charles de Gaulle were instrumental in persuading British Prime Minister Winston L. S. Churchill to offer the French, albeit unavailingly, an indissoluble Anglo-French union should they continue the fight.
After the fall of France, Monnet unobtrusively became a key member of the British Supply Commission based in Washington. There, his prewar links with numerous influential Americans, many in crucial positions within the wartime bureaucracy, proved invaluable. Monnet relentlessly lobbied the administration of President Franklin D. Roosevelt for near astronomical increases in industrial war production and for enormously expanded aid to Great Britain, playing significant roles in devising the details both of Lend-Lease aid to Britain and of the January 1942 Victory Program, which vastly expanded American wartime industrial output.
Monnet spent most of 1943 in Algiers, helping to effect a united front for France's liberation between Vichy and Gaullist Free French forces in Algiers, an organization General de Gaulle soon dominated. Monnet returned to the United States in October 1943 as France's commissioner-at-large, to negotiate presidential recognition of de Gaulle's position, a formal Lend-Lease agreement, and relief and reconstruction aid for liberated France.
Monnet returned to France in November 1945, where, as commissioner general for planning, he speedily devised the Monnet Plan for French economic revival and modernization—a scheme driven by a mixture of democratic planning and foreign economic assistance. A brilliant success, the Monnet Plan became a model for economic planning through the democratic process.
The major architect of the European Coal and Steel Community of 1950, Monnet became the president of its High Authority. He remained a passionate advocate for and driving force behind greater European unity and is widely considered the father of the European Common Market of 1957. Monnet died at Montfort-l'Amaury, France, on 16 March 1979.
Duchêne, François. Jean Monnet: The First Statesman of Interdependence. New York: Norton, 1994.; Kaspi, André. La mission de Jean Monnet à Alger, Mars–Octobre 1943. Paris: Éditions Richelieu, 1971.; Monnet, Jean. Memoirs. Garden City, NY: Doubleday, 1978.; Roussel, Eric. Jean Monnet, 1888–1979. Paris: Fayard, 1996.