Vinnychuk N. Political opposition as an institution of modern democracy.

The analysis of the main approaches of political opposition's definition: functional and structural. Proposed author's formula of political opposition as organized political force that criticizes power and control it. Distinguished and systematized political opposition's functions and types in modern democracy's systems. Main opposition's functions in democracy political system are interest representation, political communication, critic and provider of alternatives, serving as a release and outlet of the public's frustrations, helping the disciplining of conflicting interests. Investigated such types of political opposition as structural - nonstructural, parliamentary - extra-parliamentary, active - passive, responsible - irresponsible, loyal, nonloyal and semi-loyal. Main stages of development's institution of political opposition are researched: