Vote matching
In light of my previous post, I’d like to suggest a vote-matching scheme. Let’s start with an example:
Suppose there’s a presidential election between Kodos, Kang, and Washington. Kodos and Kang seem to be the leading candidates.
Alf and Beth are trying to decide who to vote for. They both like Washington, but they don’t want to waste their votes. Alf thinks Kodos is the “lesser of two evils,” while Beth prefers Kang.
If Alf votes for Kodos and Beth votes for Kang, as they are inclined to do, then their two votes will “cancel out,” at least in the race between Kodos and Kang. This means that if they both agree to switch their votes to Washington, the balance of votes between Kodos and Kang will not change. Washington gets two extra votes!
This sort of vote-matching should be able to benefit some third-party candidates in real life, too. The key requirement is that voters who prefer the third-party candidate disagree about which of the two front-runners is worse. In that case, two voters can promise to vote for the third-party candidate instead of their “lesser of two evils.” If this sort of vote-matching scheme took off, I think we could see a big change in politics.
Why stop at 2 people?
Comment by Anonymous — September 23, 2009 @ 1:34 pm
This works for 2N people. Just do the same thing N times.
Comment by Peter de Blanc — September 23, 2009 @ 5:17 pm
Reminds me of Nadertrading.
Comment by Nick Tarleton — September 23, 2009 @ 5:34 pm
How does this help Alf or Beth in a way preferential voting doesn’t already, without the communication and computing overhead?
If the answer is ‘it doesn’t', then I can report that we already use preferential voting in Oz, and our political environment is still pretty stinky. The proportional system that we use in our Senate, and I believe NZ uses for their parliament is said to benefit minor parties and independents, which reduces the risk of a 2 party stranglehold by tending to distribute the balance of power among several smaller groupings.
Comment by andrewc — September 25, 2009 @ 5:31 am
Andrew: First of all, I should point out that Alf and Beth don’t get to decide how their country runs elections. This is, in fact, the situation most people are in.
To address your question: that depends on what sort of preferential voting we’re talking about. My favorite sort of preferential voting is Condorcet voting, and the sort of strategic voting I’m advocating should eventually lead to the election of Condorcet winners. So if you already had Condorcet voting, then there’s no need for this sort of strategizing.
But since you mentioned Australia, I suppose you’re talking about Instant Runoff Voting, which is a pretty bad system. I’m not sure if it’s as bad as plurality voting, but I definitely wouldn’t call it good. I haven’t looked at the cabal equilibria in instant runoff votes, so I’m not sure what the result of strategic vote-matching would be. If I were to hazard a guess, I would say that maybe cabal equilibria in IRV also elect Condorcet winners (as is the case in plurality and approval voting), but IRV is pretty chaotic so I’m really not sure.
Comment by Peter de Blanc — September 27, 2009 @ 12:09 am
Here’s another way the electoral process could potentially be subverted. Let’s say I and a bunch of friends have all fallen in love with score voting. Instead of casting our votes normally in the first-past-the-post system, we fund a fully scientific poll to figure out who score voting would probably elect, then vote for that candidate.
Comment by John Maxwell IV — February 25, 2010 @ 3:57 am
The problem I see with this is that in a close race between Kodos and Kang (where Washington has little chance of winning), Alf or Beth might insincerely agree to vote matching each other. It’s a decent stop-gap, but switching to a more expressive ballot is ultimately necessary, yeah?
Comment by Brad Beattie — March 20, 2010 @ 9:59 pm
Отличная статья +++ Автору респект!
Comment by Чукчов — September 4, 2010 @ 6:51 am