A more common form of an electoral system is known as the Proportional Representation (PR). There are many variations to this system.
“In such systems, elections may (Germany) or may not (Israel) take place within smaller geographic units, but even if they do, each unit elects a number of officials, with each party winning seats in proportion to the vote it receives.”
Fiorina, Morris P. The New American Democracy . 5th ed. New York: Pearson Longman, 2007. Print.
Example of PR http://4.bp.blogspot.com/_H6XW_a4TYus/Si1R5LYEImI/AAAAAAAAA3o/I8zQDmHsJ24/s1600/european+parliament+2009.bmp
Since it is not necessary to finish first in order to win seats, like it is in an SMSP system, the leaders of parties are less likely to abandon their separate organizations to combine with others. This would require them to sacrifice some of their beliefs.This allows voters to maintain allegiance to their smaller parties and a multi-party system is born.