On Voting for Third Parties

Cross Posted on my blog, By Way of Con­tra­dic­tion.

Anti-Trig­ger Warn­ing: There is not re­ally any poli­tics in this post. I doubt it will kill your mind.

If your fa­vorite can­di­date in an elec­tion is a third party can­di­date, should you vote for him?

This ques­tion has con­fused me. I have changed my mind many times, and I have re­cently changed my mind again. I would like to talk about some of the ar­gu­ments in both di­rec­tions and ex­plain the rea­son for my most re­cent change.

Con 1) Vot­ing for a third party is throw­ing your vote away.

We have all heard this ar­gu­ment be­fore, and it is true. It is an un­for­tu­nate con­se­quence of the plu­ral­ity vot­ing sys­tem. Plu­ral­ity is hor­rible and there are all bet­ter al­ter­na­tives, but it is what we are stuck with for now. If you vote for a third party, the same can­di­date would be elected as if you did not vote at all.

Pro 1) The prob­a­bil­ity that you vote changes the elec­tion is neg­ligible. All your vote does is add one to the num­ber of peo­ple who voted for a given can­di­date. Your vote for the third party can­di­date there­fore mat­ters more be­cause it is chang­ing a small num­ber by rel­a­tively more.

This ar­gu­ment is ac­tu­ally an em­piri­cal claim, and I am not sure how well it holds up. It is easy to study the like­li­hood that you vote changes the elec­tion. One study finds that it roughly varies from 10^-7 to 10^-11 in Amer­ica for pres­i­den­tial elec­tions. How­ever, it is not clear to me just how much your vote af­fects the strate­gies of poli­ti­cal can­di­dates and vot­ers in the fu­ture.

Pro 2) The prob­a­bil­ity that your vote changes the elec­tion or fu­ture elec­tions is neg­ligible. The pri­mary per­sonal benefit for vot­ing is the per­sonal satis­fac­tion of vot­ing. This per­sonal satis­fac­tion is max­i­mized by vot­ing for the can­di­date you agree with the most.

I think that many peo­ple if given the choice be­tween chang­ing the next pres­i­dent be­tween the two pri­mary par­ties or be­ing paid an amount of money equal to the product of the amount of gas they spent to drive to vote and 10^7 would take the money. I am not one of them but any of those peo­ple must agree that vot­ing is a bad in­vest­ment if you do not con­sider the per­sonal satis­fac­tion. How­ever, I think I might get more satis­fac­tion out of do­ing my best to change the elec­tion, rather than plac­ing a vote that does not mat­ter.

Con 2) Ac­tu­ally if you use a re­flex­ive de­ci­sion the­ory, you are much more likely to change the elec­tion, so you should vote like it mat­ters.

Look­ing at the prob­lem like a time­less de­ci­sion agent, you see that your choice on vot­ing is prob­a­bly cor­re­lated with that of many other peo­ple. You vot­ing for a pri­mary party is log­i­cally linked with other peo­ple vot­ing for a pri­mary party, and those peo­ple whose votes are log­i­cally linked with yours are more likely to agree with you poli­ti­cally. This could bring the chance of chang­ing the elec­tion out of the neg­ligible zone, where you should be de­cid­ing based on poli­ti­cal con­se­quences.

Pro 3) Your moral­ity should en­courage you to vote hon­estly.

It is not clear to me that I should view a vote for my fa­vorite can­di­date as an hon­est vote. If we used the anti-plu­ral­ity sys­tem where the per­son with the least votes wins, then a vote for my fa­vorite can­di­date would clearly not be con­sid­ered an hon­est one. The “hon­est” vote should be the vote that you think will max­i­mize your prefer­ences which might be a vote for a pri­mary party.

Pro 4) Strate­gic vot­ing is like defect­ing in the pris­oner’s dilemma. If we all co­op­er­ate and vote hon­estly, we will get the fa­vorite can­di­date of the largest num­ber of peo­ple. If not, then we could end up with some­one much worse.

The prob­lem with this is that if we all vote hon­estly, we get the plu­ral­ity win­ner, and the plu­ral­ity win­ner is prob­a­bly not all that great a choice. The ob­vi­ous vot­ing strat­egy is not the only prob­lem with plu­ral­ity. Plu­ral­ity also dis­cour­ages com­pro­mise, and the re­sults of plu­ral­ity are changed dras­ti­cally by hon­est vote split­ting. The plu­ral­ity can­di­date is not a good enough goal that I think we should all co­op­er­ate to achieve it.

I have de­cided that in the next elec­tion, I will vote for a pri­mary party can­di­date. I changed my mind al­most a year ago af­ter read­ing Stop Vot­ing for Nin­com­poops, but af­ter re­cent fur­ther re­flec­tion, I have changed my mind back. I be­lieve that Con 1 is valid, Con 2 and the other crit­i­cisms above ad­e­quately re­spond to Pro 1 and Pro 2, and I be­lieve that Pro 3 and Pro 4 are in­valid for the rea­sons de­scribed above. I would love to hear any opinions on any of these ar­gu­ments, and would love even more to hear ar­gu­ments I have not thought of yet.