Abstract
This paper first explores the polarizationthesis, according to which between 1990-2010 political polarization increased to a large extent in the Hungarian political elite and among citizens, although it did not undermine the stability of the political system. Second, it gives an endogenousexplanation for this phenomenon. Third, through theoretical discussion and empirical examples taken from Hungarian politics it is revealed that although growing polarization has not generated regime instability, it reduces, or might reduce, the efficiency of the operation of democracy. Five mechanisms of the effects of ideological polarization which weaken democratic accountability are explored.