Question

Reconstruction of Europe and Japan
Why the United States felt compelled to rebuild Europe and Japan?
Japan: What specific changes were made, and by whom?
The Marshall Plan: What it did, why, and its impact on communism and Cold War and the European economies?

Answer 1

After the war, a new war started up: the Cold War. The Soviets, who were once our buddies, were now our rivals and we needed allies against them in the coming conflict. It was in our best interests to have a strong Europe and an ally in the far East to check the spread of Communism as well as open up business opportunities.

Democratic reforms were introduced to Japan and the emperor was made a figurehead with no real political power. Most of the changes were instituted under General MacArthur who was the Allied commander placed in charge of overseeing the reconstruction of Japan. MacArthur was smart enough to know that completely gutting the government wasn't the real answer and removing the emperor would be a mistake given how much reverence the Japanese held towards him. At the same time, he made it clear that the government would be a democratic one. Huge business concerns (zaibatsu) were also broken up because of their resemblance to monopolies.

At the same time, the Marshall Plan was instituted in Europe to rebuild the nations shattered in the war. Most of it focused on rebuilding their economic infrastructure, trade, and modernizing manufacturing capabilities to accelerate their growth with an eye towards the long game. Under the plan, the US loaned out money to help rebuild Europe. By the time the plan had ended, many of the nations (who represented the West as the Soviets and its allies did not want to take part in the Plan seeing it as a hook into their own economies) ended up at higher productivity levels than they had been before the war.

The goal of the plan was simply to strengthen Europe against Communism and the idea was to make these nations strong enough to resist the Soviets. In the end, it's probably safe to say that it succeeded in drawing the line in Europe.