The “party system” is the whole of political parties in a certain State and
the elements which characterize its structure: the number of parties; the
relations among them, consideration of their magnitude as well as their
relational forces, their ideological and strategic locations, are all elements
to determine the ways of interaction and the nature of relations.
With respect to the number of political parties existing in a given
political system, reference is made to multipartisanship, bipartisanship, or
unique party. Regarding dictatorial or totalitarian forms of government, it can
be said of a unique party system (as it happened in the fascist regimes, or
Communist China or the Soviet Union) that it is not about institutions derived
from a democratic process, but rather structures for power preservation.
Bipartisanship (as in the United States and England, for example) is
identified as derived from an electoral system based on a majority principle,
while the multipartisanship system (such as in Germany, Belgium, Finland, The
Netherlands and Switzerland) is identified as an effect from the proportional
representation system. This reductionist way of analysis establishes a line of
connection between fragmentation (multipartisanship-proportional representation)
and polarization (bipartisanship-majority), which has made to consider that
either one system or the other contributes to the crisis and lack of stability
of the democratic system.
Other criteria disregard quantitative typology in order to favor competition
or are not within the political party system.