Why did the United States open relations with the Soviet Union in 1933?

The only time the United States appeared to have civil relations with the Soviet Union was during the 1930's and 1940's.  Prior to that time, the US had actually backed the "White" Russians during the Russian Revolution which began in 1917 and continued into the 1920's. Unfortunately, that was the losing side, and the new communist government didn't forget it.  Great Britain, on the other hand, had watched with growing interest the Soviet Experiment, and believed that communism was indeed the way of the future; much of Soviet business, industry, and technology was seeded by them.  In fact, counter to the remainder of the industrialized world, the Soviet economy expanded during the Great Depression.  By 1933, during the nadir of the Depression,  Germany elected a new leader; the US saw more danger in Hitler than Stalin, and for the remainder of the Depression and World War II, the Soviet Union under "Uncle Joe" was our best ally.  After the World War, the Cold War began, and the US and USSR remained at odds until 1989 until the Soviet Experiment was no more. Politics makes strange bedfellows.