Why did the USSR disallow US help in Poland and Czechoslovakia?

The USSR did not wanted the US to hold power over Poland and Czechoslovakia.

Explanation:

After World War II, Joseph Stalin wanted Communist countries to protect the USSR. By 1950, the Eastern Bloc consisted of many Eastern European countries, including Hungary, Poland, Ukraine, and Czechoslovakia. The Soviet Union intervened militarily in Hungary, Czechoslovakia, and others to hold their power. The USSR rejected the US to help because of political differences. The USSR believed in communism where the US wanted to spread democracy.

nativists tried to get rid of the immigrants as they thought they were going to ruin the u.s.  

d. promised it other land