First past the post system

First past the post (FPTP) voting, also known as single member district plurality (SMDP), is an electoral system in which voters cast a single vote for a candidate in a single district, with the winner being the candidate who gains more votes than any other candidate. FPTP is one of the oldest and simplest electoral systems and is common in countries which adopted the Westminster system of government.

Advocates of FPTP note that it often leads to the dominance of two large parties (this empirical observation is known as Duverger's Law) and that a two party system has certain advantages:

• It usually leads to stable majority government.
• Unpopular governments can be completed rejected by relatively small changes in voting behaviour.
• It is difficult for extremist parties to gain significant representation in the legislature.
• Those elected need to have regard to local issues in order to be reelected.

The most serious criticism of FPTP is that it often leads to disproportionate results, an extreme example of which was the 2001 election in British Columbia in which the Liberal Party gained 57% of the vote but won all but two of the 79 seats in the legislative assembly. As a consequence various types of proportional representation have become common in democracies. Critics claim other disadvantages of FPTP:

• Voters in closely fought districts get more attention from the parties than those in 'safe seats'.
• It is possible for a whole region to be completely unrepresented by a major party, for example the Conservative Party won no seats at all in Scotland in the 1997 United Kingdom General Election.
• It is particularly vulnerable to certain types of tactical manipulation, such as compromising (when a voter thinks their preferred candidate has no chance of winning they may vote for a less preferred candidate so that their vote has a chance of affecting the outcome) and vote splitting (where two similar candidates share the votes that either would have got alone, allowing a less popular candidate to top the poll).
• Smaller parties can only get representation if they concentrate their support in particular areas, so encouraging nationalist or separatist parties such as the Scottish National Party and Bloc Québécois.