The Molotov–Ribbentrop Pact and the Winter War
The 1939 Molotov–Ribbentrop Pact clarified Soviet–German relations and enabled the Soviet Union to bring pressure to bear on the small Baltic republics and Finland, perhaps in order to better its strategic position in Eastern Europe in case of a widening of the war. The Baltic republics soon gave in to Soviet demands for bases and troop transfer rights, but Finland continued to refuse. As diplomatic pressure had failed, arms were resorted to, and on November 30, 1939, the Soviet Union began an invasion of Finland—the Winter War.
The Winter War produced in Finns a rude awakening to international politics. Condemnation by the League of Nations and by countries all over the world seemed to have no effect on Soviet policy. Sweden allowed volunteers to join the Finnish army, but did not send military support, and refused passage to French or British troops—which were in any event made ready in lower numbers than promised. Even right-wing extremists were shocked to find that Nazi Germany did not help at all, and also blocked material help from other countries.
The Moscow Peace Treaty, which ended the Winter War, was perceived as a great injustice. It seemed as if the losses at the negotiation table, including Finland's second largest city, Viipuri, had been worse than on the battlefield. A fifth of the country's industrial capacity and 11% of agricultural land were lost. Of the 12% of Finland's population who lived in the lost territories, only a few hundred stayed, the remaining 420,000 moving to the Finnish side of the new border.