After 1931 rising unemployment and political unrest led to the February 6, 1934 riots. The left banded together and formed the Popular Front, led by SFIO socialist leader Léon Blum, which won the elections in 1936. Ultra-nationalist groups also saw increased popularity, although democracy prevailed until 1940. Economic conditions did not significantly improve, even as the Popular Front reduced the workweek to 30 hours. Fearful of a civil war in France, as was happening in Spain, France led the major nations to call an arms blockade designed to prevent arms shipments to either side during the Spanish Civil War. This effort nonetheless failed to stop arms shipments from Germany, Italy and the Soviet Union.