For the majority of the nineteenth century, United States’ foreign policy, particularly with Europe, revolved around the belief that America should not involve itself in any international conflicts or disputes. This policy is called "isolationism." It faded from preeminence towards the beginning of the twentieth century, when the United States ascended as a world power and began to embark on its own path of imperialist conquest. Isolationism has occasionally resurfaced throughout American history, such as around the time of World War One and of World War Two.

In the first half of the twentieth century there were competing ideologies about how best to govern a nation—democracy, fascism, and socialism. Fascism— particularly as seen in Spain under Franco and Italy under Mussolini—is defined by an extreme form of nationalism in which the media is under complete control of the state and individual rights are limited. It also generally features a totalitarian leader whose authority cannot be questioned.

All of these countries were ruled by Fascism at some point in the twentieth century except Russia, which transitioned first from monarchy to socialism, and then towards the end of the twentieth century (with the fall of the Soviet Union) to limited democracy.

A government or military policy of deliberately killing a group of people based on social, religious, ethnic, or national reasons is called genocide. Genocides have occurred throughout human history but were particularly prominent in the twentieth century. The Holocaust was a genocide of Europe's Jews and Romani perpetrated by Nazi Germany. Hersey is speaking out against organized religious doctrine; to be ostracized means to be banished or sent away from a community; excommunication is a form of banishment carried out by the Catholic Church where individuals, or whole communities, can be shut off from the salvation provided by and through the Church.

The correct answer is "Japanese Internment." Executive Order 9066 (partially reproduced above) authorized the military to forcefully relocate and corral, well, anyone-it was completely discretionary. Of course, it was used almost solely to relocate those of Japanese descent and place them into "internment" camps; essentially, it was the forced relocation and detainment of those of Japanese descent, in large part a response to the bombing of Pearl Harbor (December 7, 1941).

The Treaty of Versailles was signed in 1919 between Germany and the Allied powers. It represents the end of World War One. Aside from ending World War One, it is notable for creating the circumstances that led to World War Two; by imposing punishments and blame that were too stringent on Germany, The Treaty of Versailles created the conditions that led to the rise of Nazism in Germany.

The Nobel Peace Prize was first given out in 1901, so Abraham Lincoln is immediately disqualified, regardless of his wonderful accomplishments. The correct answer is that Woodrow Wilson was awarded the Nobel Peace Prize in 1919, for his work in founding the League of Nations in the years immediately after World War One.

Decolonization, in which the majority of European powers lost most of their foreign colonies, either willingly or unwillingly, took place in the years immediately after World War Two. Primarily this took place from 1946 to 1966. It was a time period that witnessed Britain and France in particular, but all the European powers, abandoning their massive imperial landholdings and returning to small nation-states. The primary motivating factors were the declining wealth and influence of European powers following the horrors of World War Two; the increased importance placed on individual and national rights in the second half of the twentieth century; and pressure from the United Nations and the United States.

The GI Bill was issued in 1944 as part of an extended program to help returning World War Two veterans reintegrate into American society. It provided, among other things, housing loans and grants for access to higher education. It is considered a very important factor in the creation of the massive American middle class.

The correct answer is "Isolationism." Put simply, the US was rather gun shy after the first world war. The unequaled level of destruction and loss of life of the first world war really put war into perspective, for both citizens and government, and led to a brief period of isolationism. In addition to the fact that WWI had just ended, the fact that the beginning of the second world war took place entirely in Europe (exactly like WWI) led isolationists to believe that intervention was the worst possible course of action. Thus, isolationists counseled avoidance of conflict at all cost. 

This is reflected in the preface of the "Neutrality Act" of 1935 (reproduced above). Note that the Act utterly and totally prohibits the export of arms to any belligerent, regardless of whether they were friend or foe.