Coali&on in a Plurality System: Explaining Party System Fragmenta&on in Britain

Transcription

1 Coali&on in a Plurality System: Explaining Party System Fragmenta&on in Britain Jane Green, Ed Fieldhouse, Chris Prosser 2 September 2015, UK Elec@on Conference, UC Berkeley and Bri@sh Poli@cs Group

2 Minor party vote and seat shares Other Vote Share Other Seat Share

3 A Theory of Coali&on Effects: Increasing Support for Minor Par&es Strategic literature: PR systems, any party) 'Threshold insurance policy' : a minor party supported to ensure a preferred coali@on 'Coali@on- targeted duvergerian vo@ng' : a vote for a second preference if the second preference has bever chance of being in coali@on Balancing strategy' : shixing own party s policies in case of coali@on modera@on/compromise Sincere Vo@ng (new contribu@ons to coali@on literature) Greater influence in coali@on with larger electoral mandate Influence in coali@on means minor party vote less wasted Major party compromise means major party vote more wasted Expressive sincere vo@ng when major party differences blurred

4 Hypotheses hypothesis: of a coali@on government increases support for minor par@es and decreases support for major par@es Strategic vo@ng hypothesis: Expecta@ons of a coali@on government increases votes for minor par@es among exis@ng major party supporters Sincere vo@ng hypothesis: Expecta@ons of coali@on government increases votes for minor par@es among exis@ng minor party supporters Plurality Duvergerian hypothesis: Expecta@ons of coali@on government increases support for major par@es and decreases support for minor par@es when a least preferred party may win locally.

5 Variables of govt before and during campaign How likely do you think it is that the Labour party will form a government on its own? (0-10 scale) Policy- maximizing: chance of influence in government Which of these par@es do you think has no real chance of being part of the next UK government (either forming a government by itself or as part of a coali@on)? Policy- maximizing: Likelihood of party winning in cons@tuency How likely is it that each of these par@es will win the General Elec@on in your local cons@tuency? (0-100 scale)) Controls Like- dislike for each party (combined with propensity to vote ) Age, elec@on interest

6 Data and Methods Post- vote choice for Lib Dems, UKIP, Greens, Plaid Cymru, SNP versus for Con Lab specific logit: pooled model, all English respondents Strategic (logit) models: major party supporters who vote for minor Sincere (logit) models: minor party supporters who vote for minor And whether minor party voters more likely to desert if perceive close local race between and Labour and think hung parliament likely. Exclude respondent if no minor party candidate running

7 Strategic Vo&ng for Minor Par&es

8 Sincere Vo&ng for Minor Par&es

9 LiHle support for plurality strategic vo&ng

10 Implica&ons increased chances of for minor in a plurality system This implies Strategic vo@ng incen@ves increased under coali@on Sincere vo@ng incen@ves increased under coali@on Coali@on effects do not require propor@onal system condi@ons LiVle evidence that local compe@@veness between major par@es drove voters back to those major par@es We need to understand the 2015 general elec@on in this light Not a return to two- party Duverger elec@on Polling miss didn t contribute to Conserva@ve victory (at least not in ways that might be assumed)

11 Coali&on in a Plurality System: Explaining Party System Fragmenta&on in Britain Jane Green, Ed Fieldhouse, Chris Prosser 2 September 2015, UK Elec@on Conference, UC Berkeley and Bri@sh Poli@cs Group