[EM] St. Louis and Pushover (Re: Reply to Rob regarding RCV)

Sun Oct 1 21:01:36 PDT 2023

Hi Chris,

I posted about our discussion in the STAR Voting Slack (see here for
signing up: <https://www.starvoting.org/get_involved>), and I quickly
received a reply from the author of this piece from June 2023:
https://voting-in-the-abstract.medium.com/the-effectiveness-of-dishonest-strategies-in-different-voting-methods-8fb9ff50a490

I could say more about the topic, but I think I'm going to just encourage
you to read what Marcus Ogren wrote (since it is incredibly apropos to our
conversation here).  I'm being a bit reckless by posting the link before
doing more than a quick skim, but from what I know about Marcus, my hunch
is that there isn't a lot of "proof by assertion" in the writeup.

Rob

On Sun, Oct 1, 2023 at 6:27 PM C.Benham <cbenham at adam.com.au> wrote:

> Rob,
>
> Is "pushover" strategy common in Australian elections, and commonly named
> by that name?
>
>
> No and no.  I've only ever come across the term here, and from that Blake
> Cretney page.
>
> Seats/districts where that would even be a theoretical possibility would
> rare. I did read a report in a newspaper
> some time in the 1980s that the conservative Liberal Party toyed with the
> idea of doing that in one seat, but rejected
> the idea on the grounds that it would undermine the perceived integrity of
> the election process and so the legitimacy
> of the winner. Bear in mind that we have "compulsory voting" which is
> popular, because it is widely accepted that
> voting is a civic duty.
>
> In that district the highly predictable FPP order was Right > Centre-Right
> > Centre-Left, or if you want the parties' names
> Liberal > Australian Democrats > Labor.
>
> It was also highly predictable that nearly all of the Labor voters would
> give their second preference to the Democrat and
> that a big majority of the Democrat voters would give their second
> preference vote to the Liberal.  (Bear in mind that truncation
> isn't allowed).
>
> In that circumstance the Liberals could have organised for some of their
> supporters to vote Labor to "rescue" that candidate
> from being eliminated, so that instead the Democrat will be eliminated and
> then the Liberal will win in the pairwise contest
> with Labor.   BTW, the Democrat was the sitting member (and it may have
> been that party's only seat in the state parliament,
> Labor and Liberal are the two major parties).  Of course the Democrat was
> the Condorcet winner, but no-one  even had that
> concept.
>
> This claim you make is interesting:
>  "[STAR] somehow doesn't 'violate monotonicity' and yet [...] is more
> vulnerable to Pushover than RCV (aka IRV) which does.".
>
> Is that true?
>
>
> Yes.
>
> It seems to me that RCV's series of runoffs lead to many opportunities for
> weak candidates to snowball via transfers from eliminated candidates.  The
> snowball effect in RCV usually snowballs to the center of public opinion,
> but can sometimes roll toward the outskirts as candidates get eliminated
> and their ballots get transferred to a stronger and stronger candidate on
> the outskirts.
>
>
> Now you are just talking about things connected with RCV's clone
> independence and slight "extremist bias". Nothing to do with Pushover.
>
> With STAR (and Score), I believe the candidate needs to have strong
> support from all voters to get a high enough score to advance (since all
> ballots are considered in the runoff round), but perhaps similar
> polarization can occur under STAR over time.
>
> This is also completely irrelevant to Pushover strategy (which doesn't
> necessarily have anything to do with polarization).
>
> It's truly an interesting question which method is more susceptible to
> pushover.
>
> As a matter of simple logic STAR is much more susceptible.  The aim of the
> Pushover strategist is create a two-candidate final consisting of his
> favourite plus a "turkey".
> (I've come across the term "turkey-raising" from a US source about voting
> methods. Maybe it means the same thing as pushover.)
>
> One of the dangers for the strategist is that his favourite won't make it
> into the final, perhaps being displaced out of it by the turkey.  This
> danger is obviously much lower
> for the STAR strategist because (unlike the RCV strategist) he can fully
> vote to help his favourite into the final as well as the turkey.   The RCV
> strategist has to fully rely
> on other voters to get his favourite into the final.
>
> The second danger for the Pushover strategist is that in the final the
> "turkey" might win. In that final the RCV strategist has to actually vote
> for the turkey and hope that
> his vote is overwhelmed by others.  The STAR strategist doesn't have that
> problem. He can choose between "pushover-lite" where he gives the turkey
> the second-highest
> possible score so that his vote still helps his favourite beat the turkey
> in the final,  and "full" pushover to maximise his help for the turkey into
> the final in which case in the
> final his vote merely has no effect.
>
> Chris Benham
>
>
> On 1/10/2023 7:14 pm, Rob Lanphier wrote:
>
> Hi Chris,
>
> I'm going to reply to your original email (and quote it on the bottom).
> I'm going to replace "SCORE" with "[STAR]" in your email, because you
> agreed in an earlier mail that's what you meant
>
> I have a lot clearer idea of what the "pushover" strategy is now, thanks
> (at least partially) to your email (thank you!).  My hunch is that the
> pushover strategy may not be as well-studied, but it may be that there's
> different terminology used in academic circles (perhaps "pied piper"...see
> below).  I'm assuming from your email address that you're Australian.  Is
> "pushover" strategy common in Australian elections, and commonly named by
> that name?   My hunch is that pushover is a bigger problem in IRV/RCV/STV
> than it is in more consensus-oriented election methods (like approval, any
> Condorcet system, STAR).  I ask this because we don't talk about "pushover"
> here in the United States, but it wouldn't surprise me if Australians talk
> about it a lot.  We don't have very many places using STV/IRV/RCV, and the
> politics of those places (e.g. San Francisco, Cambridge Mass) are treated
> like outliers in mainstream political conversation.  San Francisco has
> weird politics (which I assert from my office in San Francisco)
>
> There are more places that use "top-two open primary" (like California and
> Washington state).  "Pushover" hasn't (yet) made it into the mainstream
> political lexicon in either place (that I know of), but I do know that in
> 2022, the Democratic Party here made a point of trying pushover against the
> Republicans in regular first-past-the-post primaries :
>
> https://www.washingtonpost.com/politics/2022/09/12/democrats-interfere-republican-primaries/
>
> It was a risky strategy, but (I'm sad to say) it probably worked in 2022.
> It failed for Hillary Clinton in 2016 though (see this 2016 article about
> Clinton's "pied-piper strategy"):
>
> https://www.salon.com/2016/11/09/the-hillary-clinton-campaign-intentionally-created-donald-trump-with-its-pied-piper-strategy/
>
> This claim you make is interesting:
>  "[STAR] somehow doesn't 'violate monotonicity' and yet [...] is more
> vulnerable to Pushover than RCV (aka IRV) which does.".
>
> Is that true?  It seems to me that RCV's series of runoffs lead to many
> opportunities for weak candidates to snowball via transfers from eliminated
> candidates.  The snowball effect in RCV usually snowballs to the center of
> public opinion, but can sometimes roll toward the outskirts as candidates
> get eliminated and their ballots get transferred to a stronger and stronger
> candidate on the outskirts.  With STAR (and Score), I believe the candidate
> needs to have strong support from all voters to get a high enough score to
> advance (since all ballots are considered in the runoff round), but perhaps
> similar polarization can occur under STAR over time.  It's truly an
> interesting question which method is more susceptible to pushover.
>
> As for the monotonicity of STAR, I'll need to leave it as an exercise for
> the reader.  I'm not sure anyone has proven that STAR is monotonic, though
> I suspect that an example of non-monotonic STAR would be a really weird
> edge-case.
>
> Rob
> p.s. I've replaced "SCORE" with "[STAR]", but won't correct your spelling
> of "maximising" nor "favourite", even though my spell checker really wants
> me to.  English-speaking people are one people, separated by common
> language.  :-)
>
> On Sat, Sep 30, 2023 at 1:07 AM C.Benham <cbenham at adam.com.au> wrote:
>
>> Rob,
>>
>> A question for Chris (anyone who cares to answer), what's the best
>> explanation of pushover at a public URL that seems reasonably academically
>> rigorous (e.g. something that seems like it would pass muster as a citation
>> on English Wikipedia)?
>>
>>
>> Blake Cretney (who used to be active here) had a web-page  ("
>> condorcet.org" I think it was called)
>> that is unfortunately now extinct. I regret not copying and storing the
>> definitions/explanations that
>> were there.
>>
>> That is where "Push-over" strategy was defined.  As I recall it said
>> something simple like
>> "the strategy of promoting a weak alternative for it to be beaten by a
>> preferred stronger one".
>>
>> But really I think we are in the realm of common-sense and the bleeding
>> obvious rather than being
>> in awe of and deferring to academic authority.  Whatever it is exactly
>> called, in the US political system it must be commonplace.
>>
>> Because (at least in some states) you have open public party primaries.
>> Suppose you are a supporter of party A, and either you are happy with all
>> the candidates running in A's primary election (or you are confidant that
>> your favourite can win that primary without your help, or something in
>> between) and so you decide to instead vote in main rival party B's primary
>> to vote not for your sincere lesser evil but for the candidate you think
>> would have the smallest chance of beating the A candidate in the general
>> election.
>>
>> You would be using a Push-over strategy.
>>
>> Likewise suppose the method is plurality Top-Two Runoff.  If you are
>> confident that your favorite can make it into the top two without your help
>> then in the first round you might vote for a candidate (of course
>> preferably among the other front-runners for the second spot) that you
>> think most likely to lose in the runoff against your favourite. Then in the
>> final you can vote sincerely.
>>
>> If the method is approval TTR, things are much easier for the pushover
>> strategists because they don't have to rely on on other voters to get their
>> favourite into the final two, and also they don't have to limit themselves
>> to promoting just one weak candidate.
>>
>> If you only care about electing your favourite, the obvious strategy is
>> to approve your favourite and all the candidates that you are confident can
>> neither displace your favourite out of the top two or pairwise beat your
>> favourite in the final.
>>
>> [STAR] is similar.  There one can choose between maximising the chance
>> that a weak candidate will get in to the final two, or weakening your vote
>> for the weak candidate to just below maximum (4 instead of 5) so as to help
>> your favourite win the top-two pairwise comparison.
>>
>> In comparison with the methods I've so far mentioned in RCV (fka IRV) the
>> would-be pushover strategists face the greatest problems and risks. They
>> have to rely entirely on other voters to both get their sincere favourite
>> into the final top two and also to overcome the strategists' own votes, for
>> the strategists' sincere favourite to win the final two comparison.
>>
>> That electowiki entry you linked to:
>>
>> Pushover[edit
>> <https://electowiki.org/w/index.php?title=Tactical_voting&veaction=edit&section=4>
>>  | edit source
>> <https://electowiki.org/w/index.php?title=Tactical_voting&action=edit&section=4>
>> ]
>>
>> *Push-over* is a type of tactical voting that is only useful in methods
>> that violate monotonicity <https://electowiki.org/wiki/Monotonicity>. It
>> may involve a voter ranking or rating an alternative lower in the hope of
>> getting it elected, or ranking or rating an alternative higher in the hope
>> of defeating it. Also known as a *paradoxical* strategy. Note that it is
>> usually very difficult to successfully pull off, and often backfires (i.e.
>> elects the pushed over candidate).
>>
>>
>> The first sentence looks like something I recall from that extinct page.
>> It is correct in the universe of pure ranking methods. But according to
>> apparent consensus here (and a wikipedia page you linked to)  [STAR]
>> somehow doesn't "violate monotonicity" and yet (as I've discussed) is more
>> vulnerable to Pushover than RCV (aka IRV) which does.
>>
>> Regarding the last bit, I've no idea how the author would know that it
>> "often backfires", or have any idea how "often" it is attempted.
>>
>> Chris Benham
>>
>>
>>
>> *Rob Lanphier* roblan at gmail.com
>> <election-methods%40lists.electorama.com?Subject=Re%3A%20%5BEM%5D%20St.%20Louis%20and%20Pushover%20%28Re%3A%20Reply%20to%20Rob%20regarding%20RCV%29&In-Reply-To=%3CCAK9hOYnPv5QaWnZhEhgAK6P08XyHdA1ew1p2fRn%2B0jD58DsUkA%40mail.gmail.com%3E>
>> *Tue Sep 26 21:39:35 PDT 2023*
>> ------------------------------
>>
>> Hi Chris
>>
>> Regarding former St. Louis resident Lewis Reed's preference of voting
>> system, I'm not sure.  I suspect he was selling his preference to the
>> highest bidder, and since he was still the President of the St. Louis Board
>> of Aldermen, he presumably had influence in STL politics (until the bribery
>> case in court made him politically radioactive).  Whatever remaining
>> influence Reed may still have is waning with every day he spends in an
>> Arkansas prison, where I believe he lives today. Something tells me that
>> electoral reform is the least of Reed's worries in 2023.
>>
>> Regarding approval's potential vulnerability to pushover when used in a
>> top-two primary, I'm personally not very concerned about the theoretical
>> possibility.  Perhaps in the far future, we'll have really sophisticated
>> voters who understand how to strategically influence the primary in a way
>> that causes top-two approval to fail in a way that causes problems.  My
>> sense is that St. Louis (which uses top-two approval) has bigger problems
>> than sophisticated attempts at "pushover"
>>
>> I believe that St. Louis voters just wanted a good mayor in 2021, and
>> approved many competitors to Lewis Reed (including Tishaura Jones and Cara
>> Spencer).  From my analysis, it looks like the wealthier voters in the
>> southern portion of St. Louis (i.e. the type that pay handsomely for
>> produce at farmers' markets in mall parking lots on the weekends to assuage
>> their guilt for the collapse of the independent farming in the United
>> States) voted for Cara Spencer.  The voters in the northern part of the
>> city (in the floodplain at the confluence of the Missouri and Mississippi
>> Rivers, which USUALLY doesn't flood very much) voted for Tishaura Jones.
>> Given the demographics of St. Louis (43% Black, 42.9% non-Hispanic White,
>> 5.1% Hispanic, 4.1% Asian, 1.0% Hispanic White), it seems like a Tishaura
>> Jones was a great choice to succeed their longtime White mayor.  Northern
>> St. Louis is largely Black and Hispanic, and it's in really rough shape,
>> despite having some fantastic old brick houses and lots of fantastic real
>> estate that is available for very little money (see <https://youtu.be/SPyjYQALnrE>).  Jones is the first Black mayor of St.
>> Louis since 2001, and third Black mayor that the city has ever had (and the
>> first Black woman in the role).
>>
>> Based on my cursory research, I'm not sure the "pushover" phenomenon is
>> well known outside of the jargon-speaking electoral reform community (and
>> perhaps not even here).  Note that the electowiki section about pushover
>> has no citations, and the "push over" section of a similar article on
>> English Wikipedia even has the infamous "citation needed" tag:
>>
>>    - https://electowiki.org/wiki/Tactical_voting#Pushover
>>    -
>>    https://en.wikipedia.org/wiki/Tactical_manipulation_of_runoff_voting#Push_over
>>
>> Note: the "Push over" section appears to have had the "citation needed"
>> banner on it since 2009, which means that said banner is almost old enough
>> to get its driver's licence in many places.  I have a hard time taking the
>> criterion too seriously given that it doesn't seem to warrant its own
>> article on English Wikipedia.  It seems all of the important ones have
>> articles:
>>
>>    -
>>    https://en.wikipedia.org/wiki/Comparison_of_electoral_systems#Compliance_of_selected_single-winner_methods
>>
>> A question for Chris (anyone who cares to answer), what's the best
>> explanation of pushover at a public URL that seems reasonably academically
>> rigorous (e.g. something that seems like it would pass muster as a citation
>> on English Wikipedia)?
>>
>> Rob
>>
>> p.s. having driven through St. Louis many times (and even stayed there a
>> couple of nights), it's not hard to guess where the powers-that-be drew the
>> red lines:https://storymaps.arcgis.com/stories/366759e8b76c46efbf6ff9e8fff3ac0b
>>
>>
>> ----
>> Election-Methods mailing list - see https://electorama.com/em for list
>> info
>>
>
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