Yes, at least, the colonists considered it so. It made it very difficult and expensive for all colonists to get goods.
Both western europeans and latin american people could immigrate "freely" under that immigration act. The act was intended as a mean to limit the immigration of people whose ancestry was "non white", while increasing the number of "white" inmigrants to guarantee a more homogeneous population in the US. The first group of people was allowed to immigrate because many people living in the US came from the british islands, and in the case of latin american people, since they were a mixture of european and native american parents, they were considered as "white", too. People not allowed to immigrate under this act: asians and east europeans.
It was the Truman Doctrine.
The Iron Curtain was the metaphorical barrier that seemed to split the Eastern Bloc from Western Europe. It was first mentioned by Churchill. The Berlin Wall was the physical embodiment of this "Curtain" that was constructed by the USSR to prevent Eastern Europeans from migrating. The Marshall Plan sent $13 billion to European nations to help them rebuild after WWII. The Truman Doctrine was specifically put in place to contain communism by aiding nations that were "at risk" so they would not turn to communism to solve their problems.
Yeah, it might be! Who knows.?
The Soviet Union did this because they wanted to rebuild and expand their country after massive destruction and loss of life during the war. Essentially this aggressive expansion and annexing of these countries made the world realize that the Soviets were a massive threat to the world even though they were allies during WWII. I hope this helps :)
