View
216
Download
0
Category
Preview:
Citation preview
The UK Party System and Party Politics
Part 1: The electoral dimension
Patrick Dunleavy
Gv 311: British Politics course, Lecture 9 Michaelmas Term 2014-15
•London School of Economics © P. Dunleavy 2014
A ‘party system’ is constituted by
a. How voters behave
b. Electoral institution effects, favouring one or more parties over others
c. Party ideologies and cleavages
d. Governance institutions favouring some parties
e. How parties recruit elites and how they behave in office and opposition
f. How much parties shape public policies
This week I cover
1. Duverger’s Law, and how it completely ceased to apply in the UK
2. Current trends and characterizing the GB party system now
3. The role of disproportionality (measured as DV scores) in sustaining major party dominance at general elections
4. Tracking party system expansion with the effective number of parties (ENP)
• Plurality rule (‘first past the post’) elections always produce/ tend to encourage the emergence of a two-party system. Formulated in 1955 at height of post-war re-growth period.
• Initially framed at national level, but that pattern soon collapsed
• Then re-framed to apply only within local electoral districts (constituencies)
• Supplementary Duverger’s Hypothesis – proportional systems encourage more parties to emerge and survive
Duverger’s Law
Source: Dunleavy and Diwakar, 2013. Analysing multiparty competition in plurality rule elections, Party Politics, vol 19: p.855
‘Mechanical’ and ‘psychological’ mechanisms in Duverger’s Law
• Andrew Cox’s 1997 reformulation says – for any electoral system the maximum number of parties per district N = M + 1 (where M is district magnitude).
• In plurality rule, M size = 1, so UK maximum number of (effective or major?) parties per constituency should = 2
• Nationalization of parties is a separate issue driven by regional identities etc – so Cox’s theoretical max N for UK could be 646 x 2 = 1292. A pretty safe bet here!
Duverger’s Law updated
• Under plurality rule, a social group with 67%+ support in a constituency can split two ways, knowing they will still always beat the opposition
• Splitting majority vote is rational in maximizing the welfare of the majority of the majority – MP closer to their view
• Implies – we should never see a top party
P1 > 67%
• If opposition also splits, the majority social group may fragment further, yet still win
Dickson and Scheve (partial) counter-theory
0
10
20
30
40
50
60
70
80
90
100
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100To
tal vo
te f
or
all o
ther
part
ies in
each
ele
cto
ral
dis
tric
t
Top national party lead over second national party in each electoral district
Double APT
Crown
Top national party ahead of 2nd Second national party ahead of top
67% 67%
Second national
party
Topnational party
Second national party wins local majority
Top national partywins local majority
The Crown diagram
USA House of Representatives district-level outcomes 2006 election
- USA is almost the only modern super-Duvergerian two-party system
0
10
20
30
40
50
60
70
80
90
100
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Republican lead over Democrats in each electoral district
To
tal v
ote
fo
r a
ll o
the
r p
art
ies
in
ea
ch
ele
cto
ral d
istr
ict
Double APT
Crown
Republicans ahead of DemocratsDemocrats ahead of Republicans
67%67%
A non-Duvergerian pattern – the Indian district-level outcomes in the
2004 general election. 43 parties in Lok Sabha, 18 in coalition government
Constituency outcomes in the 1955 general election, in Great
Britain - then a predominantly two-party system
0
10
20
30
40
50
60
70
80
90
100
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Conservatives lead over Labour in each local seat (%)
To
tal v
ote
sh
are
fo
r a
ll o
the
r p
art
ies
(%
)
Conservative MPs
with a local majority
Labour MPs with
a local majority
Other MPs
with a local
majority
Constituency outcomes in the 2010 general election, in Great Britain
0
10
20
30
40
50
60
70
80
90
100
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Conservative lead over Labour in each local seat (%)
To
tal vo
te s
hare
fo
r all o
ther
part
ies in
each
seat
(%)
Labour MPs with
a local majority
Conservative MPs
with a local majority
Other MPs
with a local
majority
67% 67%
0
10
20
30
40
50
60
70
80
90
100
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Conservative lead over Labour in each local seat (%)
on
serv
ati
ve lead
over
Lab
ou
r in
each
lo
cal seat
(%)
Conservative MPs
with a local majority
Labour MPs with
a local majority
0
10
20
30
40
50
60
70
80
90
100
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Conservative MPs
with a local majority
Labour MPs with
a local majority
0
10
20
30
40
50
60
70
80
90
100
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Conservative MPs
with a local majority
Labour MPs with
a local majority
0
10
20
30
40
50
60
70
80
90
100
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Conservative MPs
with a local majority
Labour MPs with
a local majority
South-east North-west
ScotlandWales
The patterns of constituency outcomes across four different regions in the 2010 general election
Rows consistent with Duverger’s Law
Comparing with other countries
Election districts with a given number of parties receiving 1% or more of local votes
United States, House of
Representatives 2006
Indian general election 2004
Great Britain, general election
2005
One 7.8 0 0 Two 52.6 3.9 0
Three 29.0 13.8 3.5 Four 9.2 23.4 32.3 Five 0.7 26.7 41.1 Six 0.2 18.4 17.5
Seven 0.2 8.6 4.9 Eight 0.2 3.1 0.6
Nine or more 0 2.0 0 Total 100% 100% 100%
No of cases 435 546 628
The UK party system now
1. GB has not been a ‘two-party system’ since 1974 - nor a 2.5 or 3 party system since 2000
2. In terms of voting Great Britain is a standard European multi-party system
3. Voters’ multi-partism has previously been artificially suppressed by plurality rule voting at general elections
Trends in the vote shares for the top two parties and for
smaller parties, 1970 to 2010
80 79
50 50
62
4046
5348 45
3530
0
10
20
30
40
50
60
70
80
90
100
1966 1970 1974
FEB
1974
OCT
1979 1983 1987 1992 1997 2001 2005 2010
Two party (Con plus Lab) Two party lead over Rest Liberal Democrats All other parties
Note: The numbers in grey area here show the combined Conservative and Labour per cent support, minus
the combined support for the Liberal Democrats and all other parties, that is the ‘two party lead over the Rest’.
40
50
60
70
40
50
60
70
80
90
100
Com
bin
ed %
Con a
nd L
ab v
ote
s
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Election y ear
The decline of the Labour and Conservatives two party system at general elections since 1950
% o
f Seats
wh
ere
Lab
vs C
on
are
top
2 p
artie
s
1974 hung
Parliament
1983 Labour slump: SDLP
New Labour period
Source: Prof Ron Johnston, Bristol
Party running top in 2014 Euro election votes, by local authority areas
SNP
UKIP
Lab
Con
Lib Dem
Source: House of Commons Library, European Parliament Elections 2014, Research Paper 14/32, 11 June 2014. http://www.parliament.uk/business/publications/research/briefing-papers/RP14-32/european-parliament-elections-2014
% vote share
Lab Con Lib Dem
UKIP Greens Rest Lab lead
2005 36 33 23 2 1 5 + 3
2010 29.5 37 23.5 3 1 6 -7.5
2013 EP
25.5 24 7 27.5 8 8 +1.5
Polls (Nov 2014)
33 32 8 15 5 7 + 1
State of the Parties since 2005
The 2014 party system, in England
Conservative
centre
Labour Lib
Dems
BNP Greens
UKIP
left right
Respect
Con Lab LD SNP SSP Grn
The Scottish party system
UKIP
Conservative
centre
Labour Lib
Dems
BNP Greens
UKIP
left
Respect
The English party system
A lot has changed - the 2010 English party system
Conservative
centre
Labour Lib Dems
Con Lab LD SNP Grn
- the 2010 Scottish party system
BNP GREEN UKIP
UKIP
left
left
right
right
SSP
Respect
BNP
Three key motors of party system change despite the non-reform of Westminster and local voting
• Class dealignment • PR elections since 1997, introducing new
voting systems, especially the Supplementary Vote, Additional Member System, and List PR – broadening voters’ experience nationwide
• Multi-tier elections – European elections, and devolved governments in Scotland, Wales and London (+ Northern Ireland) – so-called cross-tier “contagion effects”
Occupational class
Conservative Labour Liberal
Democrat
Other
parties Total
Upper non-manual
(AB) 39 26 29 7 100%
Routine non-manual
(C1) 39 28 24 9 100%
Skilled manual (C2) 37 29 22 12 100%
Unskilled manual/ not
working (DE) 31 40 17 12 100%
Per cent of each ‘occupational class’ voting for
main parties, general election 2010
Source: Ipsos MORI (2010) ‘How Britain Voted 2010’. http://www.ipsos-mori.com/researchpublications/researcharchive/poll.aspx?oItemId=2613
DV (deviation from proportionality) score
• We calculate the differences in seats shares compared with votes shares for each party
• Add up all the scores ignoring + or - signs
• Divide by 2 to remedy double-counting
• Gives DV score • Note: Minimum DV score is 0% No maximum DV score – unless all MPs go to a party with no votes at all, which is not a democracy
Party Vote
%
Seats %
Deviation
Con 35 45 +10
Lab 30 38 +8
Lib 20 7 -13
Other 5 0 -5
Total (Ignore = or -) 36
Deviation from Proportionality
18%
‘Deviation from proportionality’ scores, 1992-2012
Practicable minimum score for any voting system is around 4%
17.4
21
22.4
20.7
22.7
0 5 10 15 20 25
1992
1997
1999 Scotland
1999 Wales
1999 Europe
2000 London
2001
2003 Scotland
2003 Wales
2004 London
2004 Europe
2005
2007 Scotland
2007 Wales
2008 London
2009 Europe
2010
2011 Scotland
2011 Wales
2012 London
Deviation from proportionality score
Plurality election
‘Deviation from proportionality’ scores, 1992-2012
Practicable minimum score for any voting system is around 4%
E
E
E
17.4
21
22.4
20.7
22.7
10.3
10.6
13.9
14.8
12.1
14.1
14.8
13.7
10.2
17.7
8.1
11.7
11.8
14.7
12.1
0 5 10 15 20 25
1992
1999 Scotland
1999 Europe
2001
2003 Wales
2004 Europe
2007 Scotland
2008 London
2010
2011 Wales
DV
score
Plurality election British AMS (PR) election
Local DV scores in the 2010 general election By Chris Hanretty (Univ of East Anglia) The darker the colour, the higher the DV score in the 30 seats around constituency X
Durham
South west
Source: Democratic Audit blog, 5/10/2013 http://www.democraticaudit.com/?p=1496
Local DV score %
Counting parties – the ENP score
• We calculate the effective number of parties (ENP) by squaring the decimal vote shares, summing and dividing 1 by the sum
• The squaring process weights the contribution of large parties highly, and marginalizes that of small parties
• Here 1 divided by 0.312 = 3.21 parties
Party Vote Vote sq
Con .38 0.144
Lab .35 0.123
Lib .20 .04
Others .07 .005
Total 0.312
‘Effective number of party’ scores since 1992
Practicable minimum score for any voting system is around 1.5 parties
0 1 2 3 4 5 6 7
1992
1999 Scotland
1999 Europe
2001
2003 Wales
2004 Europe
2007 Scotland
2008 London
2010
2011 Wales
Effective number of parties
Plurality election
2.21
3.06
2.63
3.4
3.6
3.3
3
4.7
4.2
3
5.8
4.65
4.59
4.57
3.5
4.4
3.5
0 1 2 3 4 5 6 7
1992
1999 Scotland
1999 Europe
2001
2003 Wales
2004 Europe
2007 Scotland
2008 London
2010
2011 Wales
EN
P
Plurality election British AMS (PR) election
‘Effective number of party’ scores, 1992-2012
Practicable minimum score for any voting system is around 1.5 parties
‘Effective number of party’ scores, 1992-2012
Practicable minimum score for any voting system is around 1.5 parties
2.21
3.06
2.63
3.4
3.6
3.3
3
4.7
4.2
3
5.8
4.65
4.59
4.57
3.5
4.4
3.5
4.3
5.1
6.3
0 1 2 3 4 5 6 7
1992
1999 Scotland
1999 Europe
2001
2003 Wales
2004 Europe
2007 Scotland
2008 London
2010
2011 Wales
EN
P
Plurality election British AMS (PR) election Euro election
Outcomes of the European Parliament elections in Great Britain in 1999, 2004 and 2009, using regional list PR systems
0
10
20
30
40
50
60
70
80
90
100
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Conservative % lead over Labour in each local seat
To
tal %
vo
te s
ha
re f
or
all o
the
r p
art
ies
in
ea
ch
lo
ca
l
se
at
2009 2004 1999
Conservatives ahead of Labour Labour ahead of Conservatives
67%67%
Crown
Recommended