officials, the Nazi Party, and German industrialists for acts of aggression against the Soviet Union, which he described as "the most heinous crime". The governments-in-exile represented in the London International Assembly lobbied for a formal international tribunal with jurisdiction over acts of aggression. In 1944, Trainin proposed that the Nazi leaders could be dealt with either with a tribunal or by "the political verdict of the victorious democratic States". At this time, the Soviet Union still perceived itself as vulnerable to international aggression, motivating its interest in criminalizing aggression. Although there was not much in the way of international criminal law to work from, in ten months the United States Department of War put together the legal framework for the Nuremberg trials. Some prominent United States policymakers thought that execution without trial compromised the principles of the Allies, and that formal trials before an international court would lend legitimacy. At the 1945 London Conference, the victorious Allies decided to criminalize aggression and try their vanquished enemies, although at the conference doubts were raised that wars of aggression were illegal under customary law. Both the Soviet Union, which invaded the Baltic States and Poland according to the secret protocols of the German–Soviet pact, and Western countries that had planned an invasion of Norway were aware that they could also be accused of acts of aggression, so they limited the definition of crimes against peace to the actions of their defeated enemies during World War II. Case law Almost all the trials for crimes against peace took place between November 1945 and November 1948, though in some cases such as Romania they extended into 1949; no one has been prosecuted for aggression before or since. The courts faced the challenge, first of proving the criminality of acts of aggression, and secondly in tying such acts to individuals. War-responsibility trials in Finland In 1939, the Soviet Union invaded Finland, leading to a peace treaty on unfavorable terms in 1940. In 1941, Finland attacked the Soviet Union, retaking the ceded territory and occupying parts of the Soviet Union that had never been part of Finland. In 1944, the war turned against Finland, which signed an armistice on even less favorable terms. The Allied Control Commission in Finland insisted on holding trials for aggression during the second war, as the armistice had required Finnish cooperation in trying those accused of war crimes. The law establishing