WWI Experiences of Italy and America

Italy
Italy had only become a unified state in 1870, and hadn't developed its own culture yet. WWI brought social disruptions when the resentful veterans and patriots who weren't happy with the amount of territory they had received because of the Treaty of Versailles. By switching sides partway through the war they screwed themselves.
During the depression, many things threatened the Italian social order because of many strikes. The answer to this was Benito Mussolini. He took the jobless veterans and promised to change the order of rule away from communism and democratic rule. He focused on building state power. Democracy was ended and people who put up a resistance were deported. Although Mussolini was an atheist, he embraced the Catholic Church. All of this was the beginning to a new Italy.

United States
As a result of WWI the United States was the center of global power. It had contributed to the defeat of Germany, and its financial resources had evolved the United States into Europe's creditor. President Wilson's 14 Points inspired a new type of international life. However, this failed. Germany had been punished too severely in his opinion, and the United States refused to join the League of Nations that HE had suggested.
The depression brought many social and cultural changes to the Americans. On the day the stock market crashed, eleven Wall Street financiers committed suicide. Banks were shut down, and many people lost all of their money. Worst of all was the loss of work. Unemployment was everywhere, and it reached 30% by 1932. Empty businesses began to symbolize the severity of the depression.

All of this info comes from Robert W. Strayer's Ways of the World