A Unitary State, in contrast with a Federalist or Confederal state, is a state that is dominated exclusively by the central Federal government. Many of the modern European powers are Unitary States, but the United States of America is a Federal state, where powers are shared between the central government and the states.

Categorical grants issued by the United States government are issued with a fixed and narrow purpose in mind. The money is given to local or state governments under the assurance that it will be used for a specific purpose decided at the Federal level, often education. They differ from block grants, which offer the local or state government a much broader scope for the use of the money.

Dwight D. Eisenhower warned against the dangers of the military-industrial complex in his farewell speech given on January 17, 1961. Eisenhower's critique of the military-industrial is considered particularly resonant, and informed, since he was, prior to his political career, a five-star general and the supreme commander of the Allied forces during the invasion of Nazi Europe.

Isolationism was a foreign policy that was dominant in the American political arena throughout the majority of the nineteenth century. It argues that the United States will not get involved in foreign conflicts and will try to remain isolated on the international stage.

The League of Nations was part of Woodrow Wilson’s Fourteen Points, which he released on the eve of the end of World War One. The idea was to form an international body that would oversee international affairs and try to prevent another global conflict from breaking out. It failed in part due to a lack of support in the United States: it failed even to pass Congress, much to Wilson’s dismay.

NATO was created in 1949 as an alliance of the United States, Canada, Western Europe, and Turkey to meet the perceived threat of the Soviet Union and the rise of communism. It was primarily a military alliance. Its opposition was the Warsaw Pact, which was formed shortly afterwards between Russia and the communist nations of the Eastern Bloc.

Appeasement is the term given to making concessions to a political or military rival in order to prevent said rival from doing something even worse. It has long been a controversial form of making policy and is most notable in US History for America’s reaction to the Japanese occupation of Manchuria in 1931.

Throughout the initial decades of the Cold War, the United States and the Soviet Union continued to acquire more and more nuclear weapons until each nation possessed the capacity to destroy the planet many times over. In an attempt to mitigate this massive threat to humanity, the two superpowers signed a treaty in 1972 designed to reduce the stockpile of nuclear weapons possessed by both nations. This took place during the presidency of Richard Nixon.

George Washington was particularly concerned about entering long-term alliances with foreign nations, fearing it would draw America into unnecessary conflicts. His fear of political factions warring over the government was a common fear among the founders, best expressed by Madison's Federalist No. 10. 

The idea of getting involved in foreign conflicts was incredibly unpopular in America, and the isolationist politicians in Congress tried to keep America out of both of the World Wars as long as possible before the United States eventually entered both of the wars late.