From Bloodlands: Europe Between Hitler and Stalin, by Timothy Snyder (Basic Books, 2010), Kindle Locs. 2094-2112, 2285-2321 (pp. 105, 116-117):
In 1937 Japan seemed to be the immediate threat. Japanese activity in east Asia had been the justification for the kulak operation. The Japanese threat was the pretext for actions against the Chinese minority in the Soviet Union, and against Soviet railway workers who had returned from Manchuria. Japanese espionage was also the justification for the deportation of the entire Soviet Korean population, about 170,000 people, from the Far East to Kazakhstan. Korea itself was then under Japanese occupation, so the Soviet Koreans became a kind of diaspora nationality by association with Japan. Stalin’s client in the western Chinese district of Xinjiang, Sheng Shicai, carried out a terror of his own, in which thousands of people were killed. The People’s Republic of Mongolia, to the north of China, had been a Soviet satellite since its creation in 1924. Soviet troops entered allied Mongolia in 1937, and Mongolian authorities carried out their own terror in 1937-1938, in which 20,474 people were killed. All of this was directed at Japan.
None of these killings served much of a strategic purpose. The Japanese leadership had decided upon a southern strategy, toward China and then the Pacific. Japan intervened in China in July 1937, right when the Great Terror began, and would move further southward only thereafter. The rationale of both the kulak action and these eastern national actions was thus false. It is possible that Stalin feared Japan, and he had good reason for concern. Japanese intentions were certainly aggressive in the 1930s, and the only question was about the direction of expansion: north or south. Japanese governments were unstable and prone to rapid changes in policy. In the end, however, mass killings could not preserve the Soviet Union from an attack that was not coming.
Perhaps, as with the Poles, Stalin reasoned that mass killing had no costs. If Japan meant to attack, it would find less support inside the Soviet Union. If it did not, then no harm to Soviet interests had been done by preemptive mass murder and deportation. Again, such reasoning coheres only when the interests of the Soviet state are seen as distinct from the lives and well-being of its population. And again, the use of the NKVD against internal enemies (and against itself) prevented a more systematic approach to the actual threat that the Soviet Union faced: a German attack without Japanese or Polish assistance and without the help of internal opponents of Soviet rule.
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Officially, the agreement signed in Moscow on 23 August 1939 was nothing more than a nonaggression pact. In fact, Ribbentrop and Molotov also agreed to a secret protocol, designating areas of influence for Nazi Germany and the Soviet Union within eastern Europe: in what were still the independent states of Finland, Estonia, Latvia, Lithuania, Poland, and Romania. The irony was that Stalin had very recently justified the murder of more than one hundred thousand of his own citizens by the false claim that Poland had signed just such a secret codicil with Germany under the cover of a nonaggression pact. The Polish operation had been presented as preparation for a German-Polish attack; now the Soviet Union had agreed to attack Poland along with Germany.
On 1 September 1939, the Wehrmacht attacked Poland from the north, west, and south, using men and arms from annexed Austria and Czechoslovakia. Hitler had begun his war.
In August and September 1939, Stalin was reading maps not just of east Europe but of east Asia. He had found an opportunity to improve the Soviet position in the Far East. Stalin could now be confident that no German-Polish attack was coming from the west. If the Soviet Union moved against Japan in east Asia, there would be no fear of a second front. The Soviets (and their Mongolian allies) attacked Japanese (and puppet Manchukuo) forces at a contested border area (between Mongolia and Manchukuo) on 20 August 1939. Stalin’s policy of rapprochement with Berlin of 23 August 1939 was also directed against Tokyo. The Molotov-Ribbentrop Pact between Germany and the Soviet Union, signed three days after the Soviet offensive, nullified the Anti-Comintern Pact between Germany and Japan. Even more than the battlefield defeat, the Nazi-Soviet alliance brought a political earthquake in Tokyo. The Japanese government fell, as would several more in the coming months.
Once Germany seemed to have chosen the Soviet Union rather than Japan as its ally, the Japanese government found itself in an unexpected and confusing situation. The consensus among Japanese leaders was already to expand southward rather than northward, into China and the Pacific rather than into Soviet Siberia. Yet if the union between Moscow and Berlin held, the Red Army would be able to concentrate its forces in Asia rather than in Europe. Japan would then be forced to keep its best troops in the north, in Manchukuo, in simple self-defense, which would make the advance into the south much more difficult. Hitler had given Stalin a free hand in east Asia, and the Japanese could only hope that Hitler would soon betray his new friend. Japan established a consulate in Lithuania as an observation point for German and Soviet military preparations. The consul there was the russophone spy Chiune Sugihara.
When the Red Army defeated the Japanese, on 15 September 1939, Stalin had achieved exactly the result that he wanted. The national actions of the Great Terror had been aimed against Japan, Poland, and Germany, in that order, and against the possibility of encirclement by these three states working together. The 681,692 killings of the Great Terror did nothing to make encirclement less likely, but diplomacy and military force did. By 15 September Germany had practically destroyed the Polish Army as a fighting force. A German-Polish attack on the Soviet Union was obviously out of the question, and a German-Japanese attack on the Soviet Union also looked very unlikely. Stalin had replaced the phantom of a German-Polish-Japanese encirclement of the Soviet Union with a very real German-Soviet encirclement of Poland, an alliance that isolated Japan. Two days after the Soviet military victory over Japan, on 17 September 1939, the Red Army invaded Poland from the east. The Red Army and the Wehrmacht met in the middle of the country and organized a joint victory parade. On 28 September, Berlin and Moscow came to a second agreement over Poland, a treaty on borders and friendship.
So began a new stage in the history of the bloodlands. By opening half of Poland to the Soviet Union, Hitler would allow Stalin’s Terror, so murderous in the Polish operation, to recommence within Poland itself. Thanks to Stalin, Hitler was able, in occupied Poland, to undertake his first policies of mass killing. In the twenty-one months that followed the joint German-Soviet invasion of Poland, the Germans and the Soviets would kill Polish civilians in comparable numbers for similar reasons, as each ally mastered its half of occupied Poland.
The organs of destruction of each country would be concentrated on the territory of a third. Hitler, like Stalin, would choose Poles as the target of his first major national shooting campaign.
Far Outliers 