In the previous thread on Thailand’s possible retrogression back to MNTV or even SNTV, Suaprazzodi asked why more countries do not use the single transferable vote, so we can find out how it might work outside of the narrow context of a few former British colonies.
I suspect there are various reasons why STV is not widely used, mostly having to do with party leaders not liking the way it undermines their own authority within their parties. After all, Irish politicians have tried more than once to get rid of STV, only to have voters reject their efforts at referendum. And in most Australian jurisdictions, it is used with an above-the-line vote that makes it relatively close to a closed-list system by giving party leaders the ability to determine how the votes of above-the-line voters (typically 90% or more of the total) are transferred.
Of course, these reasons would not be relevant to a context like Thailand, where the apparent intention of the current authorities is to undermine parties. However, in such a context, STV has another disadvantage: if those choosing the new electoral system want a highly personalized system as a means to allow the election of local (and usually conservative) notables, STV is less desirable than SNTV, because while the latter (and MNTV, too) allows election of candidates with extremely narrow bases of support (see some good examples in the Afghanistan subdomain), STV forces them to compromise and gain second (and third, etc.) preferences.
Thus STV may be undesirable to most elites for precisely the reason that its supporters say it is so good for voters: It empowers the wrong kinds of people. Voters!
(I should note that I am rather agnostic about STV. I like its voter-empowering aspects, but the small magnitudes needed to make it practical are not sufficiently favorable to the kinds of parties I tend to favor, and it is a bit too favorable to “friends and family” networks and localism for my taste. But it sure beats any NTV system–including cumulative vote–or plurality!)
Anyway, regarding STV’s use outside of that small subset of jurisdictions:
It is worth mentioning the use of STV in Estonia as the country was, for a short time, the exception to the rule that STV was only used in countries with a British imperial background.
STV was used for local elections in December 1989 and for a national election in 1990. The use of STV clearly occurred at a time of significant social, political and regime change within Estonia and Eastern Europe more generally. The choice of STV for elections was a
compromise decision made by the major political parties in Estonia at that time. These were: the Communist Party of Estonia (CPE), Popular Front of Estonia (PFE), and the Joint Council of Work Collectives (JCWC). Taagepera (1998) comments on the reason for this compromise as follows:
â€œIt [STV] was adopted because it satisfied the Communist need to avoid party
lists and labels while still leading to vague proportional representation. The
district magnitude (seats per constituency) was left to the discretion of local
powerholders, which satisfied the JCWC, because they could and did chose
one-seat districts in the north-east, reducing STV to Australian-type alternative
The rules surrounding the use of STV also varied from those used in other countries. As noted
in the above quote, the number of candidates elected in each constituency varied from one to
five candidates with the number of candidates from each seat being determined by local county
and local authorities. A legacy of the Soviet era was that a turnout of at least 50% was required
before an election result could be considered valid. In addition, the electoral rules also required
â€œa candidate must attain 50% of the first place votes in order to win election. If
not, then a runoff election was to be held in which the top two contenders were
to be pitted against one another (if there were ties between three or more
candidates for first place and two or more candidates for second place, then the
number of second place votes received acted as a tie breaker, and so onâ€
(Ishiyama 1996, p.493).
In the context of the socio-political upheaval in Estonia during the time-period when STV was
used it is not entirely surprising that the electoral system was changed. A number of reasons
have been posited for this decision. Taagepera (1998) notes that some parties criticised STV
for weakening emerging party structures whilst also commenting:
â€œmany Estonians were uneasy about their inability to figure out how the votes
were converted into seats, and they suspected opportunity for fraud, although
no formal complaints were lodgedâ€ (p.31).
Ishiyama (1996) also notes that STV was perceived as inhibiting the emergence of political
parties and noted that this made STV â€œdangerous for a country beset by regionalism and the
potential for ethnic conflictâ€ (p.499).
The quoted text–and sorry for the poor formatting–is a quotation from a study prepared for the Scottish Parliament, “The Single Transferable Vote in Practice,” by Stephen Herbert. It is available in PDF.