Was the U.S. successful in stopping the spread of communism in Europe prior to 1950?
3 answers
That depends entirely on what is meant. The Soviet Union was given the rights to occupy most of Eastern Europe at the Yalta conference in 1945, so most of Eastern Europe ended up "behind the iron curtain" with communist governments. After that, communism did not spread, and both Greece and Austria were "saved" from communism. So, yes and no.
No.
http://www.skwirk.com/p-c_s-14_u-116_t-311_c-1051/communism-after-1945-background/nsw/communism-after-1945-background/australia-in-the-vietnam-war-era/the-spread-of-communism-after-the-second-world-war
http://www.skwirk.com/p-c_s-14_u-116_t-311_c-1051/communism-after-1945-background/nsw/communism-after-1945-background/australia-in-the-vietnam-war-era/the-spread-of-communism-after-the-second-world-war
The question is about Europe, not Asia. So, the answer is "no", considering the division of influence as a result of the Yalta conference, but yes after that.