severe extremist challenges and political and class divisions that plagued many European countries that attempted to develop social democratic systems after 1911. By dealing early, cooperatively, and effectively with the challenges of industrialization and its impact on Swedish social, political, and economic structures, Swedish social democrats were able to create one of the most successful social democratic systems in the world, including both a welfare state and extensive protections of civil liberties. When the Social Democratic Party came into power in 1932, its leaders introduced a new political decision-making process, which later became known as "the Swedish model" or the Folkhemmet (The People's Home). The party took a central role, but tried as far as possible to base its policy on mutual understanding and compromise. Different interest groups were always involved in official committees that preceded government decisions. Foreign policy 1920–1939 Foreign policy concerns in the 1930s centered on Soviet and German expansionism, which pursuing abortive efforts at Nordic defense co-operation. Sweden during World War II Sweden followed a policy of armed neutrality during World War II, although thousands of Swedish volunteers fought in the Winter War with Finland against the Soviets. Sweden did permit German troops to pass through its territory to and from occupation duties in Norway, and supplied the Nazi regime with steel and ball-bearings. The dominant historiography for decades after the war ignored the Holocaust and used what it called the "small state realist" argument. It held that that neutrality and co-operation with Germany were necessary for survival since Germany was vastly more powerful, concessions were limited and were only made when the threat was too great. Neutrality was bent but not broken; national unity was paramount; and in any case, Sweden had the neutral right to trade with Germany. Germany needed Swedish iron, and Sweden had nothing to gain and much to lose from an invasion. The nation was run by a national unity government, which included all major parties in the Riksdag except the communist party. Its key leaders included Prime Minister Per Albin Hansson, King Gustav V, and Foreign Minister Christian Günther. Humanitarian aid to Jews facing the Holocaust was the mission of Swedish diplomat Raoul Wallenberg. As the secretary of the 1944 Swedish delegation to Hungary, to co-ordinate humanitarian relief for the Jews of Europe during the Jewish Holocaust. He helped to rescue tens of thousands of Jews in Nazi-occupied Hungary in