Churchill's speech was widely broadcast in the USA,
mainly because of his reputation.
At this stage of the Cold War there were many US politicians
who were not anxious to tie themselves to Britain. They were concerned about
getting dragged into conflicts to preserve Britain's empire which were no
concern of the USA.
Some US politicians wanted to withdraw from world affairs,
as they had done after the 1914-18 war.
Soviet troops were in Manchuria and Persia in 1946. They
were in Manchuria (part of China) after the occupying Japanese forces had
left. The USA had many trading interests in Asia and was concerned about a
strong Soviet presence near to important US trade and military outposts like