The nature of the Soviet occupation manifested itself in 1940, when 22,000 Poles were executed by the NKVD, a branch of the Soviet secret police, in or near a place called Katyn. The victims were unarmed prisoners, mostly civilians who had nothing to do with the war effort: professors, lawyers, engineers, physicians, teachers, writers, and journalists.
The massacre at Katyn was not part of any combat operation: the fighting in Poland had ended in late 1939. This was an attempt, by the international communist conspiracy, to eliminate the intellectual and leadership potential among the Poles.
In 1941, Stalin’s political allegiances changed. After Hitler betrayed him, Stalin joined forces with the western allies. The USSR became an ally of the United States and of England.
President Roosevelt did a quick about-face: he presented the Russians, whom he’d previously presented as enemies to the American people, as our friends and allies. Overnight, Americans were told to stop viewing the Soviets as dangerous foes, and instead embrace them as partners in the fight against Hitler.
Although Stalin’s alliances had done a complete turnaround, swapping enemies for friends and vice-versa, the communist designs on Poland did not change. The western allies, hurriedly welcoming the Soviets, overlooked the USSR’s aggression toward Poland. Historians Stan Evans and Herbert Romerstein write:
The reason for this reversal was that, between the beginning of the war and its conclusion, the Soviets had been converted from foes to allies, and in this new guise continued to press their claims on Poland. When Hitler invaded Russia, the Communists were thrown willy-nilly into alliance with England. Grateful for backing from any quarter, Churchill embraced them as newfound friends and praised them in extravagant fashion. As has been seen, similar notions would prevail at the Roosevelt White House, in terms exceeding the views of Churchill. The pro-Soviet attitudes now suffusing Western councils would spell the doom of Poland.
At a famous series of wartime conferences, key Allied leaders met not only to coordinate the last phases of the war, but also to plan the postwar world. Among these meetings, the most famous were at Teheran in 1944, and at Yalta and Potsdam in 1945.
Stalin made his participation in the Allied war effort conditional on certain postwar demands. (Whether or not Stalin was truly able or willing to broker a separate peace with Hitler aside from the Allies, they yielded to his desires.)
Foremost among such demands was that the Soviets keep the part of Poland they had seized in 1939 in common cause with Hitler. Despite efforts by some in the State Department to oppose this, and occasional statements to the contrary by FDR, the Americans and British would concede the point early on, with virtually no resistance. Tentatively at Teheran, more definitely at Yalta, they agreed to bisect the prewar territory of Poland and consign roughly half of it to Russia.
President Roosevelt, it later became clear, was suffering from a variety of physical ailments which prevented him from thinking clearly at these conferences. Quite aside from the post-polio symptoms which he’d had for over two decades, by 1944 FDR was dealing with hypertension, cancer, and heart failure.
At the Yalta conference, in February 1945, Franklin Roosevelt was not simply ill. He was dying. By April of that year, he would be dead.
Participants at the conference were shocked by his condition. He fell asleep in the middle of conversations, and answered questions with nonsequiturs.
He was in no condition to participate in complex political, economic, and military analyses, even with the most honest of allies, let alone with the wily and deceitful Stalin.
In the end, the USSR received 77,000 square kilometers of Polish territory as a reward for having murdered thousand of innocent Polish civilians.