David Henderson recently diagnosed American political parties’ presidential primaries as being afflicted with the tragedy of the commons. A tragedy of the commons exists when actions that are best for each individual are actions that, if taken by all or many individuals in the group, significantly damage the settings in which these individuals act. This damage is so severe that, over time, all individuals in the group are made worse off.

The Tragedy of the Commons in the Abstract…

The classic example of a tragedy of the commons is a pasture in an agricultural village. If the pasture is treated as an ‘open-access’ resource which everyone is free to use as they wish, then each family in the village has an incentive to graze its cows and sheep without restraint. The family reaps the full benefit of each minute of additional grazing, while the resulting reduction of grass on the pasture is a cost borne by all villagers. Each family reasons that if it were to try to preserve some grass on the pasture by restricting its animals’ grazing time, the only result would be that that grass would almost immediately be eaten instead by animals belonging to other families. So even if every family is aware of the danger of overgrazing, none of them has incentives to restrict the grazing of its own animals. Further, no one has an incentive to reseed the pasture. The reason is that the cost of the reseeding would be borne fully by the family doing the reseeding while the benefits would be enjoyed by all families, most of whom didn’t contribute to the reseeding effort.

The pasture is overgrazed and soon becomes bare. Actions that for everyone are individually rational can lead to outcomes that for everyone are tragic.

In this case, an obvious and easy solution exists: Privatize the pasture. If the pasture is privately owned, the proprietor will earn positive income by charging grazing fees. The owner’s desire to keep this stream of income flowing incents him both to reseed the pasture when necessary and to prevent animals from overgrazing. Because the costs of the owner’s failure to take these steps would fall with disproportionate weight on him, we can be confident that, to avoid these costs, the owner would take these costly but worthwhile steps.

… and Applied to Politics

So what does the above have to do with politics?

As of the date of this writing (June 8^th, 2023) there are nine formally declared candidates for the 2024 Republican presidential nomination. This number includes Donald Trump. Many (most?) Republicans – along with many independents – plausibly worry that if Donald Trump wins his party’s 2024 nomination, not only are Republicans destined to lose next year’s presidential race, Trump will also doom so many GOP congressional candidates that both houses of Congress would again become strongholds of the Democrats. Indeed, one prominent Republican stalwart, Peggy Noonan, believes that putting Trump at the top of the 2024 GOP ticket would ensure the party’s literal destruction.

In the old days, when presidential nominees were chosen by party chieftains meeting in smoke-filled rooms, no party would choose as its nominee a candidate with such bleak prospects for the general election as those of Donald Trump. Party chieftains were akin to owners of the party; they had incentives to ensure that the party put forth the candidate with the best prospects of winning the White House.

Today, however, each political party is a ‘commons.’ It has no owner or any clique of people to act as owners. No one with any authority to change the party’s course oversees the party as does the owner of a pasture oversee the operation of the grazing land to which he has title. One result is that there is ‘overgrazing’ for votes. With nine (and potentially still more) candidates vying for the GOP’s 2024 nomination, each candidate personally enjoys the prospect of winning the ultimate prize, but an important cost of his or her participation in the race is borne by – “externalized on” – others. This important cost is the diverting of votes cast in primary elections away from candidates who have genuine prospects of winning the general election. If enough such votes are diverted away from ‘good’ candidates, the possibility is real that the candidate who by the end of the primaries will have won the largest number of votes is a ‘bad’ candidate – a candidate with only the slimmest of chances of winning the general election.

Thinking of modern-day American presidential primaries as settings in which the tragedy of the commons is at work is very helpful. But additional insight is beneficial – namely, recognition of the importance of distinguishing votes for from votes against. A voter who, when in the voting booth, pulls the lever marked “Candidate Smith” is typically described as voting for Smith. But this description isn’t always correct; indeed, it can be highly misleading.

Suppose there are eight candidates on the ballot in addition to Jones, and that Ms. Voter despises Jones but is largely indifferent to the other eight candidates. So she votes for Smith. But had Smith not been on the ballot she would have voted with nearly equal enthusiasm for any of the candidates other than Jones. In this example – which is hardly far-fetched – Ms. Voter’s vote is not so much for Smith as it is against Jones. And what’s true for Ms. Voter might be true for a large number of her fellow voters who cast their ballots for candidates other than Jones. Because the number of non-Jones candidates is large, the “anybody-but-Jones” vote is dispersed among several candidates, leaving each of them with a smaller vote total at the end of the election than is won by Jones.

If, at the election’s end, Jones has a majority of all the votes cast, then – while it’s never legitimate to describe Jones’s election as revealing “the will of the people” – we can legitimately conclude that that number of voters who oppose Jones is smaller than is the number who regard him as the best candidate. But if Jones wins only a plurality of the votes, then declaring him to be the nominee is fraught with this significant problem: A majority of the voters voted against Jones.

If we think of votes as “votes for” candidates, then it would make some sense to declare any candidate who wins only a plurality of votes, but not a majority, as the victor. The reason is that no other candidate has the support of as many voters as does the plurality winner. From this perspective, the plurality winner is the people’s choice. But once we recognize that votes can be “votes against,” then declaring as victor any candidate who wins only a plurality runs the very real risk of putting into office a person who the majority of voters oppose. The candidate who wins only a plurality might do so simply because the opposition vote was spread among two or more opposing candidates.

Because today a candidate is declared to be a political party’s presidential nominee if that candidate wins only a plurality of primary votes – winning an actual majority isn’t necessary – it should be no surprise if both the Democratic and Republican party each often sends into the general election candidates that a majority of that party’s voters oppose.