Many people think that political equality is obviously a good thing, an ideal toward which any decent political system should strive. Despite this -- or perhaps because of it -- some basic questions about political equality remain unanswered. What is political equality? What is good about it? Could some other ideal(s) take its place? My aim here is to answer each of these questions. In regards to the first question, I argue that political equality obtains when political power is distributed equally. Two people are political equals if, and only if, they have the same amount of political power. By 'political power' I mean (roughly) the ability to get what one wants in the political arena. Conceiving of political equality in this way allows us to accommodate both the moral and amoral dimensions of politics. What is good about political equality, so conceived? Political equality is good insofar as it leads to the equal advancement of everyone's interests. There are several reasons to think that advancing everyone's interests is important. It may be a fundamental requirement of morality, a principle of social justice, or a necessary condition of political legitimacy. Of course, an equal distribution of political power is not unique in its ability to advance people's interests equally. Indeed, I argue that an unequal distribution of power will almost always lead to a moral equal advancement of everyone's interests. This is because different people have different interests, and, depending on the circumstances, different amounts of power may be needed in order to advance different sets of interests to the same degree. Thus, it is a mistake to assume that an equal distribution of power will lead to the equal advancement of everyone's interests. If the equal advancement of interests is our ultimate goal, then political power should be distributed in accordance with a principle of sufficiency, not equality. Everyone should have whatever amount of political power they need in order for their interests to be advanced to the same degree.