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When talking about the effect of voting systems on elections, something I think is overlooked is the game-theoretic implications on the candidates. Take the se

by cthor 10y ago

When talking about the effect of voting systems on elections, something I think is overlooked is the game-theoretic implications on the candidates. Take the second diagram in the article and move the candidates around. What's the optimal strategy? To move as close to your opponent as possible, while staying closer to the centre. Now take the diagram with three candidates, and move them around. What's the optimal strategy? To move as far away from both opponents. This works even if you consider an n-dimensional space for every conceivable issue. Two-party system encourages both parties to move towards the centre. Three- (or more) party system encourages them to spread out.

brianolson 10y ago
3 parties would take up position around some population center, with some differentiation, but not too much. Probably they each move to the center of mass of the third of the population they represent, except that there's some incentive to be a little centrist of that to try and poach marginal voters from the other two parties. If a party moves too far out from center, centrist voters on their margins defect to the other two parties. I'm not sure what the penalty for being 'too centrist' is.
tristor 10y ago
> Two-party system encourages both parties to move towards the centre. Either the center has shifted on the total spectrum, or this statement isn't backed by reality. At least in the US, both major parties are moving towards the right and moving towards authoritarian positions.
- mastax 10y ago
  This is usually explained by the idea that the 'Center' moves about over time. Perhaps in this instance the center was just further right than the parties expected.
- nosuchthing 10y ago
  Either the center has shifted on the total spectrum, or this statement isn't backed by reality. At least in the US, both major parties are moving towards the right and moving towards authoritarian positions. Which seems to be a result of FPTP, which fosters the limited choice between RED/BLUE.
  - ubernostrum 10y ago
    Many countries which do not use FPTP nonetheless end up with stable long-lived de facto two-party systems. The hypothetical ideal of a many-party coalition state is rare regardless of voting system and apportionment.
    - dragonwriter 10y ago
      > Many countries which do not use FPTP nonetheless end up with stable long-lived de facto two-party systems No, they don't. Heck, even many systems that do use FPTP (e.g., the UK) support more parties with representation in the main national legislative body than the US. A two-party system isn't one where merely there are two stronger parties that tend to form governments or executive administrations.
      - ubernostrum 10y ago
        So as long as there are some seats going to other parties, you don't care if there's an uninterrupted streak of two dominant major parties such that one of them always forms and leads the government? Because that is the case in many countries, even countries which don't do FPTP, even countries which do things that people argue are good electorally, and that does not seem like a categorical improvement over what happens in, say, the US.
        dragonwriter 10y ago
        > Because that is the case in many countries, even countries which don't do FPTP, No, it's emphatically not, especially if you mean exclusively forms the government (not in a coalition.) And, if you don't mean that, it's pretty substantially weaker than the duopoly in the US. Heck, even FPTP systems that aren't also Presidential systems (another structural factor that reduces competitive parties) generally don't do what you describe, at least in the form of exclusively non-coalition governments. > and that does not seem like a categorical improvement over what happens in, say, the US. Whether the difference is merely a substantial quantitative improvement with some creatively-defined common category or a categorical improvement is ultimately immaterial.
- brianolson 10y ago
  I feel like the parties split some axis of what people want, but are both pulled well off center of the population by MONEY.
- cthor 10y ago
  The U.S. reaping these benefits from their two party system is confounded by the primaries. The "centre" of each primary is with respect to the party platform, not the general population. Presidential candidates' optimal strategy is to be centre of the party base in primaries, then centre of the entire country in the general election. (And they have to do this while avoiding accusations of flip flopping.) (And there are other confounders that apply regardless of voting system. Nobody involved is working with perfect information and nobody is a perfectly rational actor.)
  - blowski 10y ago
    It's affected by personalities. A lot of people probably voted for Trump the person, rather than Trump's policies. If that's true, his position on the diagram isn't all that important. I guess this is what you meant by "non-rational actors" - people voting for policies they don't like because they like the person saying them.
  - caspianm 10y ago
    Primary voters' optimal strategy, if voting within their preferred party, should also be to pick a centre candidate, so they will win. Could get complex if people vote in the opposing party's primary though.
- kr7 10y ago
  > both major parties are moving towards the right Not on social issues. Trump is a moderate on abortion and gay marriage. Bill Clinton passed DADT, DOMA, welfare work requirements, and his crime bill, and called for a crackdown on illegal immigration. He wouldn't be able to win the Democratic nomination nowadays. > moving towards authoritarian positions Unfortunately.
  - actuallyalys 10y ago
    I think the public is moving leftward on social issues (with the exception of abortion [0]), but I'm not sure the Republican party has been recently. I mean, the Log Cabin Republicans called the most recent platform the "most anti-LGBT in history" [1]. My sense is that Trump won the nomination by downplaying his personal views on abortion and gay marriage and pledging to nominate conservative justices. [0]: http://www.gallup.com/poll/170249/split-abortion-pro-choice-pro-life.aspx http://www.gallup.com/poll/170249/split-abortion-pro-choice-... [1]: http://www.logcabin.org/pressrelease/a-message-on-the-gop-platform-from-log-cabin-republicans-president-gregory-t-angelo/ http://www.logcabin.org/pressrelease/a-message-on-the-gop-pl...
  - tomjakubowski 10y ago
    Trump's positions on abortion don't seem particular thought-through, but he did say that he would nominate SCOTUS justices who would overturn Roe v. Wade. I don't think that's a moderate position at all. And while Trump might be less of an extremist on these issues than his fellow Republicans, the party's elected officials (including his running mate) haven't moved an inch towards the center on abortion rights. Mike Pence governed Indiana, a state with some of the tightest (and most ridiculous, honestly) restrictions on abortion in the country. https://en.wikipedia.org/wiki/Political_positions_of_Donald_Trump#Abortion https://en.wikipedia.org/wiki/Political_positions_of_Donald_...
    - zeveb 10y ago
      > Trump's positions on abortion don't seem particular thought-through, but he did say that he would nominate SCOTUS justices who would overturn Roe v. Wade. I don't think that's a moderate position at all. 'Allowing the states to determine what is allowed' seems more moderate than 'no state may meaningfully restrict something,' no?
- dragonwriter 10y ago
  > Either the center has shifted on the total spectrum, or this statement isn't backed by reality. Both statements are true (shifts in the center, including long term trends in a single direction) happen, but are orthogonal to the idea that a two-party systems results in both parties driving for the middle seize the median voter (it would just make that a moving target.) OTOH, all of the examples from experience show that two-party systems don't actually have that effect, and we have good ideas why: 1. Engagement falls off as a party's position gets further from a citizens, and 2. Political views are rarely unimodally distributed to start with, and two-party systems tend to promote more of a bimodal distribution on the main axis of variation. So, a big part of what parties position for is keeping their base engaged, not appeal to the center.
- gohrt 10y ago
  "authoritarian" isn't a left/right issue. Mao and Stalin were leftist authoritarians. Your claim that authoritarianism is non-centrist is not obvious, I don't even agree it's true.
  - deleted 10y ago
    [deleted]
  - tristor 10y ago
    > Your claim that authoritarianism is non-centrist is not obvious, I don't even agree it's true. I made no such claim. My sentence has an "and" in it.
- hash-set 10y ago
  How are both major parties moving to the right? I see California having gone leftist retardation and people fleeing that state, only to setup the same stupid ideas in other states (Nevada, looking at you).
dragonwriter 10y ago
> Two-party system encourages both parties to move towards the centre. If you assume things (unimodal distribution of preferences and/or participation [propensity to vote, in simple models that ignore campaigning] that is constant across the spectrum and insensitive to distance between the voters preference and the nearest party position) that turn out not to be true in practice, sure. In the real world, two-party systems don't usually encourage centrism, they encourage polarization. The median voter theorem is a solid mathematical result given the very simple parameters it applies to, but has less practical application to the real world than many people like to think.

by cthor 10y ago

brianolson 10y ago

3 parties would take up position around some population center, with some differentiation, but not too much. Probably they each move to the center of mass of the third of the population they represent, except that there's some incentive to be a little centrist of that to try and poach marginal voters from the other two parties. If a party moves too far out from center, centrist voters on their margins defect to the other two parties. I'm not sure what the penalty for being 'too centrist' is.

tristor 10y ago

> Two-party system encourages both parties to move towards the centre. Either the center has shifted on the total spectrum, or this statement isn't backed by reality. At least in the US, both major parties are moving towards the right and moving towards authoritarian positions.

mastax 10y ago
This is usually explained by the idea that the 'Center' moves about over time. Perhaps in this instance the center was just further right than the parties expected.
nosuchthing 10y ago
Either the center has shifted on the total spectrum, or this statement isn't backed by reality. At least in the US, both major parties are moving towards the right and moving towards authoritarian positions. Which seems to be a result of FPTP, which fosters the limited choice between RED/BLUE.
- ubernostrum 10y ago
  Many countries which do not use FPTP nonetheless end up with stable long-lived de facto two-party systems. The hypothetical ideal of a many-party coalition state is rare regardless of voting system and apportionment.
  - dragonwriter 10y ago
    > Many countries which do not use FPTP nonetheless end up with stable long-lived de facto two-party systems No, they don't. Heck, even many systems that do use FPTP (e.g., the UK) support more parties with representation in the main national legislative body than the US. A two-party system isn't one where merely there are two stronger parties that tend to form governments or executive administrations.
    - ubernostrum 10y ago
      So as long as there are some seats going to other parties, you don't care if there's an uninterrupted streak of two dominant major parties such that one of them always forms and leads the government? Because that is the case in many countries, even countries which don't do FPTP, even countries which do things that people argue are good electorally, and that does not seem like a categorical improvement over what happens in, say, the US.
      - dragonwriter 10y ago
        > Because that is the case in many countries, even countries which don't do FPTP, No, it's emphatically not, especially if you mean exclusively forms the government (not in a coalition.) And, if you don't mean that, it's pretty substantially weaker than the duopoly in the US. Heck, even FPTP systems that aren't also Presidential systems (another structural factor that reduces competitive parties) generally don't do what you describe, at least in the form of exclusively non-coalition governments. > and that does not seem like a categorical improvement over what happens in, say, the US. Whether the difference is merely a substantial quantitative improvement with some creatively-defined common category or a categorical improvement is ultimately immaterial.
brianolson 10y ago
I feel like the parties split some axis of what people want, but are both pulled well off center of the population by MONEY.
cthor 10y ago
The U.S. reaping these benefits from their two party system is confounded by the primaries. The "centre" of each primary is with respect to the party platform, not the general population. Presidential candidates' optimal strategy is to be centre of the party base in primaries, then centre of the entire country in the general election. (And they have to do this while avoiding accusations of flip flopping.) (And there are other confounders that apply regardless of voting system. Nobody involved is working with perfect information and nobody is a perfectly rational actor.)
- blowski 10y ago
  It's affected by personalities. A lot of people probably voted for Trump the person, rather than Trump's policies. If that's true, his position on the diagram isn't all that important. I guess this is what you meant by "non-rational actors" - people voting for policies they don't like because they like the person saying them.
- caspianm 10y ago
  Primary voters' optimal strategy, if voting within their preferred party, should also be to pick a centre candidate, so they will win. Could get complex if people vote in the opposing party's primary though.
kr7 10y ago
> both major parties are moving towards the right Not on social issues. Trump is a moderate on abortion and gay marriage. Bill Clinton passed DADT, DOMA, welfare work requirements, and his crime bill, and called for a crackdown on illegal immigration. He wouldn't be able to win the Democratic nomination nowadays. > moving towards authoritarian positions Unfortunately.
- actuallyalys 10y ago
  I think the public is moving leftward on social issues (with the exception of abortion [0]), but I'm not sure the Republican party has been recently. I mean, the Log Cabin Republicans called the most recent platform the "most anti-LGBT in history" [1]. My sense is that Trump won the nomination by downplaying his personal views on abortion and gay marriage and pledging to nominate conservative justices. [0]: http://www.gallup.com/poll/170249/split-abortion-pro-choice-pro-life.aspx http://www.gallup.com/poll/170249/split-abortion-pro-choice-... [1]: http://www.logcabin.org/pressrelease/a-message-on-the-gop-platform-from-log-cabin-republicans-president-gregory-t-angelo/ http://www.logcabin.org/pressrelease/a-message-on-the-gop-pl...
- tomjakubowski 10y ago
  Trump's positions on abortion don't seem particular thought-through, but he did say that he would nominate SCOTUS justices who would overturn Roe v. Wade. I don't think that's a moderate position at all. And while Trump might be less of an extremist on these issues than his fellow Republicans, the party's elected officials (including his running mate) haven't moved an inch towards the center on abortion rights. Mike Pence governed Indiana, a state with some of the tightest (and most ridiculous, honestly) restrictions on abortion in the country. https://en.wikipedia.org/wiki/Political_positions_of_Donald_Trump#Abortion https://en.wikipedia.org/wiki/Political_positions_of_Donald_...
  - zeveb 10y ago
    > Trump's positions on abortion don't seem particular thought-through, but he did say that he would nominate SCOTUS justices who would overturn Roe v. Wade. I don't think that's a moderate position at all. 'Allowing the states to determine what is allowed' seems more moderate than 'no state may meaningfully restrict something,' no?
dragonwriter 10y ago
> Either the center has shifted on the total spectrum, or this statement isn't backed by reality. Both statements are true (shifts in the center, including long term trends in a single direction) happen, but are orthogonal to the idea that a two-party systems results in both parties driving for the middle seize the median voter (it would just make that a moving target.) OTOH, all of the examples from experience show that two-party systems don't actually have that effect, and we have good ideas why: 1. Engagement falls off as a party's position gets further from a citizens, and 2. Political views are rarely unimodally distributed to start with, and two-party systems tend to promote more of a bimodal distribution on the main axis of variation. So, a big part of what parties position for is keeping their base engaged, not appeal to the center.
gohrt 10y ago
"authoritarian" isn't a left/right issue. Mao and Stalin were leftist authoritarians. Your claim that authoritarianism is non-centrist is not obvious, I don't even agree it's true.
- deleted 10y ago
  [deleted]
- tristor 10y ago
  > Your claim that authoritarianism is non-centrist is not obvious, I don't even agree it's true. I made no such claim. My sentence has an "and" in it.
hash-set 10y ago
How are both major parties moving to the right? I see California having gone leftist retardation and people fleeing that state, only to setup the same stupid ideas in other states (Nevada, looking at you).

dragonwriter 10y ago

> Two-party system encourages both parties to move towards the centre. If you assume things (unimodal distribution of preferences and/or participation [propensity to vote, in simple models that ignore campaigning] that is constant across the spectrum and insensitive to distance between the voters preference and the nearest party position) that turn out not to be true in practice, sure. In the real world, two-party systems don't usually encourage centrism, they encourage polarization. The median voter theorem is a solid mathematical result given the very simple parameters it applies to, but has less practical application to the real world than many people like to think.