In his most famous piece of work, The Prince, Niccolò Machiavelli basically wrote a manual on the types of existing principalities, poiniting out the difference between each of them, on the foundations of power and, finally, on the norms of conduct that the one who aspires to be prince must adopt. According to the author, it was not enough to achieve power; the prince should be able to keep it, and to do so, he would have to be respected by the people, acting accordingly to each circumstance, changing strategies as appropriate. The most famous saying that synthesizes the Machiavellian though is "The ends justify the means", which means that in order to remain in the custody of power (which would be the "end"), the prince is authorized to act in the most convenient manner, not necessarily needing to stick to rigid moral principles and ethical norms.
The main reason why the United States largely shied away from imperialism prior to 1890 was because it was still a relatively "fragile" nation with a host of its own issues to work out--such as the slavery issue that eventually led to the devastating Civil War.
Radical Republicans believed that African Americans deserved immediate freedom from bondage and should receive the same rights as whites. Radical Republicans favored granting civil rights to African Americans for various reasons. Some radicals truly believed that African Americans were equals to the whites.
