Why Politicians Lie

Winning a two-candidate election in which voters can be plotted on a spectrum will require winning the median voter. This is a well-known result in political science.

We usually think of the median voter theorem as applying to the left–right political spectrum, where it was first deployed. It does useful work over there, even if we can pick it apart sometimes at the margins. But let’s put it on another spectrum and see what we get.

Voters can also be ranked from low information to high. I postulate no correlation whatsoever with the traditional left-right spectrum; what I say here is true, and it stands alone.

Now let’s imagine that a political party—one bearing no postulated resemblance to either of the Big Two—set out to win the median voter on this continuum. “Being well-informed is important,” says the High Information Party, “and we pledge to have the most well-informed candidates and messaging around. If you’re especially well-informed, you should vote for us.”

The downfall of this strategy is obvious; well-informed people will still at least sometimes disagree with one another. A coalition can’t get off the ground.

But there’s still a way for the High Information Party to win the election. It can reach out to the less-informed voters using untrue claims that appeal to them. The best of these claims, of course, will be those that are also superficially plausible to some bloc of high-information voters.

And, owing to the median voter theorem, this will become the High Information Party’s only road to victory. It will stay that way just as long as well-informed people continue to disagree. Which means forever. The disagreements of the well-informed ensure that the median voter strategy will never work on a spectrum of how well-informed people are. For each marginal dissenter, the High Information Party needs to reach out to one more less-than-median-information voter.

To return to the real world: The High Information Party exists. It consists of the elite of the two major parties, who certainly know a good deal about how the country really works. But here’s their problem: To keep their jobs, they have to lie about how the country works in ways that less-informed voters will find appealing. They can’t do otherwise as long as any disagreement exists among them.

To win an electoral majority, the elites need the votes of people who — just for some examples — think that foreign aid consists of twenty percent of the federal budget, or that the government sets forty percent of prices, or that twenty percent of Americans are gay or lesbian, or that thirty-five percent of all workers make the minimum wage, or that Barack Obama is a Muslim, or that Republicans want corporations to have all the same rights as people, or that… well, you get the idea.