The Power of the Median Voter Theorem By David Henderson

Political commentator Michael Barone writes:

So despite California Democrats’ hopes that an early presidential primary date will give the state greater influence in selecting a Democratic nominee, past history suggests that that’s not likely — and that there’s a risk that California, newly installed at the left extreme of the political spectrum, will tilt the process toward an unelectable left-wing nominee.

See Michael Barone, “California Democrats’ early presidential primary: Unintended consequences?” Washington Examiner, October 2.

University of Tennessee law professor Glenn Reynolds quotes more extensively from the well-reasoned article and then comments, “I see no downside to this.”

I would have thought that the downside, from Glenn’s conservative viewpoint, would be obvious.

It’s something called the median voter theorem. The median voter theorem states that “a majority rule voting system will select the outcome most preferred by the median voter”. Definition taken from Wikipedia. The theorem applies best in a political system in which two parties dominate and in which voters can be arrayed along a spectrum. Glenn obviously believes that that applies to the current U.S. system. His thinking is that if the Democrats go further left, they will lose, which means the Republicans win.

He’s right.

But that’s where the downside comes in. If the Democrats go far to the left of the median voter, what’s the Republicans’ best response if their goal is to win? It’s to go further left themselves (not further left than the Dems but further left than they would have gone against a more-moderate Dem candidate) to pick up all the voters on their side of the median plus, say, a slice of 10% on the other side. If they go moderate left, they pick up these voters. So yes, the Republicans win. But Glenn’s cherished policies lose.

This is exactly what happened in 1972 when George McGovern was well to the left of the median voter. Nixon ran a campaign that was fairly left. I remember having just arrived in the United States in September 1972 and hearing an ad about how Nixon had used naked presidential power to shut down a polluting factory without having any particular law to draw on. “That’s a great anti-Nixon ad,” I thought when I heard it. Then I heard the end: “Young people talk; President Nixon listens.” The ad was bought by the Nixon campaign.