First past the post vs. proportional representation
Voting for Dummies - Proportional Representation System
How to break the two-party hold on American politics
Christopher Hitchens on Proportional Representation
Proportional representation (PR) characterizes electoral systems by which divisions into an electorate are reflected proportionately into the elected body. If n% of the electorate support a particular political party, then roughly n% of seats will be won by that party. The essence of such systems is that all votes contribute to the result: not just a plurality, or a bare majority, of them. The most prevalent forms of proportional representation all require the use of multiple-member voting districts, as it is not possible to fill a single seat in a proportional manner. In fact, the implementations of PR that achieve the highest levels of proportionality tend to include districts with large numbers of seats.