What Churchill wants the US and the British to do is to stand up strongly against the Soviets.
In this speech, Churchill warns that the Soviets do not respect anything but strength. He says that they despise military weakness. He argues that the Western Allies must not do anything that would look like they were being weak and were appeasing the Soviets. Churchill argues that appeasement was what allowed Hitler to get so strong. He says that appeasing the Soviets would allow them to get stronger and become more of a danger. Therefore, he says, the Western Allies need to present a strong and united front against communism.