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.