[30 points] Read this excerpt from President Truman’s State of the Union address in 1951:

All free nations are exposed and all are in peril. Their only security lies in banding together. No one nation can find protection in a selfish search for a safe haven from the storm.

The free nations do not have any aggressive purpose. We want only peace in the world--peace for all countries. No threat to the security of any nation is concealed in our plans and programs.

We had hoped that the Soviet Union, with its security assured by the Charter of the United Nations, would be willing to live and let live. But I am sorry to say that has not been the case.

The imperialism of the czars has been replaced by the even more ambitious, more crafty, and more menacing imperialism of the rulers of the Soviet Union.

This new imperialism has powerful military forces. It is keeping millions of men under arms. It has a large air force and a strong submarine force. It has complete control of the men and equipment of its satellites. It has kept its subject peoples and its economy in a state of perpetual mobilization.

The present rulers of the Soviet Union have shown that they are willing to use this power to destroy the free nations and win domination over the whole world.

The Soviet imperialists have two ways of going about their destructive work. They use the method of subversion and internal revolution, and they use the method of external aggression. In preparation for either of these methods of attack, they stir up class strife and disorder. They encourage sabotage. They put out poisonous propaganda. They deliberately try to prevent economic improvement.

Based on the excerpt you read in part A and the one you just read, how did Truman’s attitude toward the Soviet Union change between 1946 and 1951? Support your answer with at least one quotation from each excerpt.