## The costs of quadratic voting

I explained how quadratic voting works in my previous post, where I presented a simple quadratic voting procedure in which voters are allocated an equal number of “vote credits” before going to the polls. Yet, whenever we are evaluating a proposal for reform like quadratic voting, we must not only consider the benefits of the proposed reform; we must also weigh the costs of the reform as well. Does quadratic voting pass this cost-benefit test? With this test in mind, I will identify several potential problems with this method of voting.

1. The “Rube Goldberg” Objection. The most serious objection to quadratic voting is that it is too damn complicated to operationalize at an acceptable cost. Like a fabled Rube Goldberg Machine, Quadratic Voting introduces a non-trivial amount of complexity into the simple act of voting. For starters, how many “vote credits” should each voter receive? May voters accumulate unused vote credits for future elections? Will voters be allowed to transfer some or all of their vote credits to other voters? What would a “quadratic ballot” look like? What happens if a voter makes an arithmetical error when allocating his vote credits among his preferred candidates? And so on. For all its faults and imperfections, the “one-man, one-vote” rule is easy to understand and easy to operationalize, while even the simplest quadratic voting schemes, by contrast, resemble an elaborate and cumbersome Rube Goldberg machine, a device designed to perform a simple task in an indirect and overly-cumbersome way (like the elaborate “Self-Operating Napkin” contraption pictured below).

2. The “Tyranny of the Minority” Problem. Another potential problem with quadratic voting is that, despite its complexity, it is not immune to strategic voting. Specifically, a large-enough minority of intense zealots could end up overriding the will of the majority of voters by allocating their “vote credits” in a strategic manner. To see this, consider the South Carolina example from my previous blog post. To keep it simple, let’s assume that x number of Democrat voters go to the polls to choose their preferred candidate, where x = 10 voters, and let’s further assume that six of these voters prefer a moderate candidate like Amy Klobuchar, Pete Buttigieg, or Joe Biden, while the remaining four voters prefer a more radical candidate like Bernie Sanders or Elizabeth Warren. If the six moderate voters end up distributing their “vote credits” evenly among the three moderate candidates–while the four zealous voters agree to assign all of their “vote credits” to one of the radical candidates–, the radical candidate could end up winning the primary by a landslide(!), even though he or she is supported by only 40% of the voters! In fairness, this objection applies to other forms of voting as well, including the “one-man, one-vote” system, but at least with one-man, one-vote, the lack of majority support is transparent in the final vote count. Quadratic Voting, by contrast, could produce a false picture of reality, with the radical/minority candidate receiving the largest number of total votes. File under: WTF!

3. The Buterin Problem. In his excellent primer on Quadratic Voting, Vitalik Buterin identifies an important gap in all Quadratic Voting schemes: who decides what issues and which candidates get to go on the ballot in the first place? In fairness, this objection applies equally to all methods of voting: whoever has the power to set the agenda (or to decide which candidates may run for office) can strategically manipulate the agenda or ballot to achieve his preferred outcome. But this objection is especially salient in the context of quadratic voting. Why? Because even the simplest version of quadratic voting is far more complicated and elaborate that the “one-man, one-vote” rule (see Objection #1 above), so why should we adopt a more complex procedure voting if the complex method is just as amenable to manipulation as “one-man, one-vote” schemes?

Nevertheless, despite these objections, ideally we would still like to find a viable way of taking the intensity of voter preferences into account. To this end, I will present an alternative — and far more simpler — method of achieving this goal in my next post, a method I have christened “Bayesian voting.”