2020, the election campaigns have begun

[Labster]

It works great, thanks for asking.

Er, okay.  It's a very simple system for the voter, but a complex system to tally.  I have done an STV election by hand with only 9 votes and it got pretty crazy fast.

But fundamentally, every person submits a ballot ranking some or all of the candidates in the race.  Ranking more candidates never hurts the chances of the candidates above them (unlike in Borda Count).  Simple, right!

Now onto the math.  Depending on the number of candidates to be elected, a threshold of voters needed to elect people is calculated.  The simplest case, where you only elect one candidate, is normally called Instant Runoff voting; in that case threshold is 50%.  When you elect more than one seat at a time, it's called Single Transferrable Vote; in this case threshold is  100% ÷ ( seats + 1 ) -- two seats is 33.33% (repeating, of course), three seats is 25%, and so on.

Cool, on to the counting process!

1. Now we take all of first ranked votes and add them all together.
   
2. If any candidate has more votes than the threshold, that candidate is elected.  (If you're using fractional transfer -- which you should -- any excess votes given to that candidate become fractions of a vote for the remaining candidates.  So if we have a three-seat race where one candidate gets 30%, this means that they got 5% too many votes.  So each remaining ballot becomes worth 1/6 of a vote, and can go on to electing another candidate.)
   
3. If no candidate meets threshold, all of the votes of the candidate who got the least votes, and redistribute them to the next ranked candidate.  Or put another way, the lowest vote candidate loses, and is disqualified from winning -- readd each ballot as if that candidate didn't exist.  Go back to step 1.
   
4. Have enough candidates met threshold yet?  If so, stop.
   
5. Are there any ballots that no longer have a candidate?  If so, throw them on the "exhausted pile".
   
6. Are the number of remaining seats equal to the number of remaining candidates?  If so, elect everyone still not removed from the election, then stop.  (This is possible when people do not rank the entire ballot and too many ballots fall into the exhausted pile.)  Otherwise go back to step 1.
   

It's fairly complex, as I've written software to run an election. But I've seen the results of several of these election in practice, and they always tend to produce a good mix of representatives.  The usual mix from an election of 6 in my student senate was 3 from slate A, 2 from slate B, and one independent.  IRV is fine and all, but you really get more varied representation from electing more than one at the same time with STV.  So if you have a district that's 15% Green, 15% Libertarian, 33% Democrat, 25% Republican, 12% independent when electing 6, you have a very good chance of electing 1G/1L/2D/2R or 1G/1L/3D/1R.  Under the first-past-the-post system we have, you have a very good chance of electing a slate of all Democrats.

So that's what I mean, the majority party gets more or the most seats, but the minorities also get seats.  Majority rule, minority representation.  There are known issues about strategic voting in STV -- particularly in trying to influence the order that candidates lose -- but Arrow's Impossibility Theorem says that we can't have a perfect voting system.  But we could still have a better one.

The other downside is larger districts when electing multiple candidates, but you do not need to reach every voter.  You just need to reach out to your threshold worth.  So it's entirely possible to elect someone who only advertises on Spanish-language media, if that accounts for a threshold in the population.

Anyway this is all a pipe dream because any voting other than district voting is bad for minorities under the law, QED.