Executive summary re Proportional Representation (PR)
Single-winner voting systems are "nonrepresentative" but aim to pick the
highest-quality winner. PR systems (which involve multiwinner elections)
sacrifice both perceived winner quality and the accountability of politicians to voters,
but seek to produce winners more "representative" of the electorate.
Range voting is single-winner and hence not PR.
is an alternate form of Range Voting which is designed for multiwinner elections and
which is designed to exhibit proportionality.
It is called Reweighted Range Voting (RRV)
and is described in
paper #78 here.
We believe PR federal elections are
constitutional in the USA.
If they are unconstitutional then either major party can and will block PR forever
[and indeed it is already outlawed in Federal elections by a 1967 law,
Public Law 90-196 (2 U.S.C. 2c)].
If they are constitutional, then conceivably PR could be achieved in the House of Representatives
at least as far as the large states are concerned (but this probably would exacerbate
power imbalance between large versus small states); but PR would be unachievable for
the Senate, US Presidency, and state governorships.
Which approach is better: PR or single-winner? Unclear philosophically, unclear
based on historical evidence, and unclear based on economic statistical evidence.
No consensus exists.
Therefore I am unsure that PR is an improvement – but feel confident that
switching from plurality voting to
range voting is an improvement.
(It is a lot easier to understand and measure
the relative quality of single-winner voting systems since we can use
but no analogous quantity is known for multiwinner systems.)
Having PR is not a pre-requisite for escaping from 2-party domination.
We know that because the plurality + top-2-runoff(2nd round)
single-winner system led
in most or all of the large number of countries in which it has been tried,
to having more than 2 important parties.
A voting system property perhaps more important for causing 2-party domination is
failure of the NESD property.
The very fact that neither PR nor non-PR (mainly plurality-voting-based)
democracies exhibit obvious superiority
over the other suggests that a democracy based on
range voting could
be significantly superior to either (since there is good reason to believe it
will be significantly superior to plurality-based majoritarian democracy).
Instant Runoff Voting (IRV)
is not a "stepping stone" to PR because IRV leads to 2-party domination just like now,
and the two dominant parties will be motivated to block PR (and will be able to do so forever).
Range voting is a much more plausible stepping stone and there are forms of PR
that are both (a) similar to range voting and (b) seem to be better PR methods than STV methods
(Reweighted Range Voting and