On December 14 the Soviet Union was expelled from the League of Nations for waging a war of aggression. After presiding over the disastrous start of the campaign, and a disproportionally heavy death toll of Red Army soldiers, Voroshilov was replaced by Semyon Timoshenko as the commander of the front on January 7, 1940 (and four months later as People's Commissar for Defense). In mid-February, 1940, Soviet troops finally managed to break through the Mannerheim Line, and Finland sought an armistice.[123][124]