A quadruple whammy for first-past-the-post
Introduction
The British electoral system is often defended for producing workable Commons majorities, with the governing party accountable to voters rather than to other parties (Popper, 1988, Chandler, 1992, Johnson, 1992, Johnson, 1998, Norton, 1992, Pinto-Duschinsky, 1999a, Pinto-Duschinsky, 1999b). But since the 1970s, this defence has been undermined by four developments: the decline of the cube law; the increase in minor-party seats; the decreased cohesiveness of legislative majorities; and the rise in pro-Labour bias. The first three developments make workable Commons majorities less likely, and the fourth may hinder accountability by letting a party come first in votes but second in seats. The nightmare scenario for first-past-the-post’s defenders is an election which produces a hung parliament with the Conservatives first in votes, Labour first in seats, and the Liberal Democrats holding the balance of power and insisting on proportional representation (PR) as their price for supporting a government.
These diseases poisoning first-past-the-post have not been properly recognised by its defenders or critics. Its defenders know that it is imperfect, but they have not grasped how unreliable it has become. Although most recent elections have seen large government majorities, this is partly fortuitous: the winning party has usually had a big lead in votes over the second-placed party. First-past-the-post’s frailties should be clearer once the winning party’s lead in votes shrinks.
Critics of the system should also take note. Several discuss the cube law’s decline, but I will suggest that the rise in minor-party seats is more important. The increase in bias, often mentioned by critics, may not be as troubling as many imply. Meanwhile, neither critics nor defenders of first-past-the-post have spotted that decreased legislative cohesiveness aggravates the other developments. Both sides of the electoral reform debate should attend to these findings.
The four developments are sometimes related. For example, increased minor-party voting has contributed to the cube law’s decline, the rise in minor-party seats, and pro-Labour bias. However, this paper is more normative than empirical, so I discuss effects more than causes. It is the cumulative effect of these developments that matters most — a double, triple or even quadruple whammy, potentially a knockout blow.
The comparative dimension is noteworthy. No two single-member plurality (SMP) electoral systems work identically, so in this paper, ‘first-past-the-post’ only refers to Westminster elections. But similar systems have faced related problems. American congressional elections witnessed something similar to the cube law’s decline (Gelman and King, 1994), and in 2000 a president was elected with fewer votes than his opponent, under multi-member plurality voting. Minor parties have weakened SMP in Canada (Johnston, 2000). In New Zealand, minor parties and two successive biased elections contributed to wholesale electoral reform (Denemark, 2001). Every electoral system is partly contingent on exogenous factors, but SMP seems especially delicate. First-past-the-post’s problems are partly its own fault.
This paper assesses the actual effects of these factors at past elections, and their possible effects in the future. New methods are presented for investigating the cube law, bias, and the effect of minor-party seats. I conclude that the standard defences of first-past-the-post have been weakened but are still viable. However, this paper’s central message is that although first-past-the-post is still defensible in theory, electoral reform is becoming more likely in practice.
Section snippets
The decline of the cube law
In January 1950, an anonymous article in the Economist described what came to be called the ‘cube law’. At its simplest, the cube law means that in a two-party election, a party with a 1 percentage point lead in votes would have a 3-point lead in seats, and a party with a 2-point lead in votes would have a 6-point lead in seats. The article’s author, David Butler, concluded that first-past-the-post ‘exaggerates narrow majorities in votes into sizeable majorities in seats’ (Butler, 1950).
Readers
The rise in minor-party seats
As in Canada and New Zealand, minor parties have grown dramatically in recent years. In 1955, minor parties took only 4% of the UK vote; since the 1980s they have taken 24–30%. Section 2 mentioned that the geography of this increase indirectly weakened first-past-the-post by furthering the cube law’s decline. This section examines a direct effect: minor-party victories. Minor parties won just 8 seats in 1955, but by 2001 this had risen to 80. This is a problem for first-past-the-post because,
Decreased cohesiveness of government backbenchers
We have seen that hung parliaments and governments with low majorities are likelier than before. Now I shall suggest that low majorities are even more dangerous, because governing parties have become less cohesive, making government harder. Therefore, the electoral system’s declining ability to facilitate secure majorities becomes even more disturbing for its defenders. This intensifies the effect of the first two factors.
Defences of first-past-the-post frequently assume a certain view of
The increase in pro-labour bias
Bias has been widely discussed by analysts of first-past-the-post, especially since the 1992 election (see in particular Curtice and Steed, 1992, Johnston et al., 2001). This section extends their analysis by applying an alternative method for investigating bias, supplementing their focus on hypothetical outcomes by examining actual results. I also query some overly pessimistic forecasts about the Conservatives’ disadvantage in future elections.
Conclusion
This paper has examined four challenges facing the British electoral system: the decline of the cube law, the increase in minor-party seats, the decreased cohesiveness of legislative majorities, and the rise in pro-Labour bias. SMP electoral systems do not have fixed outcomes: the creation of workable legislative majorities depends strongly on external factors like electoral geography, electoral behaviour and legislative behaviour. Since at least the 1970s, these outside influences have made
Acknowledgements
I am grateful to David Butler, John Curtice, Ron Johnston and two anonymous referees for their very helpful comments and criticisms, to David Firth for technical assistance, and to Martin Range for data. An earlier version of this paper was presented at the Elections, Public Opinion and Parties conference at the University of Salford in September 2002, and I thank the participants for their comments.
References (49)
- et al.
Proportionality and exaggeration in the British electoral system
Electoral Studies
(1986) Partisan bias in British general elections
British Elections and Parties Review
(2001)- Blau, A., 2002. Seats–votes Relationships in British General Elections, 1955–1997. University of Oxford, DPhil...
The People and the Party System: the Referendum and Electoral Reform in British Politics
(1981)- Butler, D., 1950. Electoral facts. The Economist, 7 January,...
Appendix III: analysis of the results
- et al.
The British General Election of 1997
(1997) The plurality vote: a reappraisal
Political Studies
(1992)Revolts and Rebellions: Parliamentary Voting Under Blair
(2002)The electoral system: biased to Blair?
The electoral system
Electoral choice and the production of government: the changing operation of the electoral system in the United Kingdom since 1955
British Journal of Political Science
Appendix 2: the results analysed
Appendix 2: the results analysed
Appendix 2: an analysis of the results
Choosing MMP in New Zealand: explaining the 1993 electoral reform
Elections and party politics
Political Parties: Their Organization and Activity in the Modern State
The law of error
Transactions of the Cambridge Philosophical Society
A unified method of evaluating electoral systems and redistricting plans
American Journal of Political Science
The decomposition of electoral bias in a plurality election
British Journal of Political Science
A History of Mathematical Statistics from 1750 to 1930
An apathetic landslide: the British election of 2001
Government and Opposition
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