Divisions of Government
Proponents of the separation of powers bring an additional argument in its favor: they point out that the system diminishes the influence of special-interest groups over any one branch of government or over the government as a whole. It is difficult for even the strongest faction to dominate a government in which the executive is elected by the entire population, members of the legislature represent different geographical constituencies, and the judges are appointed by the executive with the approval of the legislature.
Not all states, of course, have such clear divisions of government, nor do divisions necessarily guarantee personal liberties. Parliamentary democratic systems, for example, tend to merge legislative and executive functions yet control the exercise of power by constitutional methods of sharing it. Authoritarian states may, however, be constitutionally bound to have separate organs of government yet actually concentrate power in the executive.