The term "oligarchy" refers to a form of government that concentrates power in the hands of an elite group, rather than a central figure, an elected assembly or the people at large, and the primary advantages appear to exist for the benefit of that elite group, while the disadvantages apply to the rest of the citizens who have to follow laws written to benefit that small group. Oligarchies often come about as a response to social disaster, such as the fallout in Germany after World War I or the ruling group in the fictitious country of Oceania that emerged in George Orwell's novel "1984."
Republics and democracies are fundamentally inefficient because it takes so long for the government to formulate a response to challenges in many cases. This lack of efficiency often means that the government appears incompetent. In situations like Germany after World War I, in which the economy was in shambles and the Nazi Party was prepared to step in and take power, people were willing to accept a loss of freedom in exchange for strong leadership. However, when the ruling group takes power, often the input and interests of those out of power go by the wayside.