May 4, 2004

Strategic Considerations of Nader Voters

Posted by Arcane Gazebo at May 4, 2004 3:20 PM

A common argument from Nader supporters is that by voting for Nader (or announcing intent to vote for Nader) they put pressure on Democratic candidates to adopt more liberal positions. I have lately been wondering whether this makes any sense.

Taking a simplistic one-dimensional model of policy space, suppose that a potential Kerry voter expresses a preference for Nader, and this causes John Kerry to consider a shift in his own positions to make up for this lost vote. He can move incrementally to the left in an attempt to win back this Nader voter, but by doing so he'll alienate moderate voters, and since the voter density is higher in the center of the spectrum than at the Naderite fringe, he'll end up losing votes overall with this policy shift. On the other hand, he can try to compensate for the Nader voter by moving slightly rightward to gain the support of a right-leaning moderate. Again because of the higher voter density, Kerry needs a smaller policy step to accomplish this. An even bigger advantage is that winning a moderate vote takes a vote away from Bush, and therefore puts him two votes ahead of his only realistic competitor while recovering the Naderite's vote only gains him one. This seems to imply that if declaring a preference for Nader will affect a Democratic candidate's position, it will move it rightward.

Ok, but the other way this argument is usually phrased is that the Kerry shouldn't take the left wing for granted, and this seems to hold up under the same line of reasoning: if a liberal voter declares support for Kerry regardless of whether third-party candidates who are closer to his preferences enter the race, Kerry is again free to move slightly rightward to pick up valuable swing votes.

So now it looks like no matter what the liberal voter does, he can only move Kerry's position to the right. Which in turn suggests that Kerry (if he is motivated purely by political calculation) will take the rightmost position he can. In other words, I've just reinvented the Median Voter Theorem. There's normally no equilibrium in the three-candidate case, but presumably if one candidate takes a fixed position at one end of the spectrum (as Nader has) an equilibrium may arise for the remaining two candidates, and if so it will certainly be to the right of the median voter. Therefore Nader's entry into the race moves both parties to the right. Thanks, Ralph!

I think there are two lessons here:

  1. Don't vote for Nader! (But you knew that.)
  2. Rather than attempting to change the Democratic Party's positions by threatening to vote for a third-party candidate, it is more effective to attempt to convince moderate voters of the virtues of liberalism, thereby moving the median voter to the left and forcing the Democratic Party (and the GOP!) to become more liberal in response.

But this also raises a question: if the Median Voter Theorem applies to American politics, how does the Bush administration get away with such a right-wing agenda on so many issues?

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