In the unlikely event that we get a second referendum on Brexit, here’s how it ought to be done: Arrange all the alternatives in a line in order of “hardness” of Brexit. In may be felt that Remain should not be an option, in which case we have Norway plus (a.k.a. Common Market 2.0) at one end, and no-deal at the other. Every voter chooses their favourite option from the list. The winning option is chosen to be the one for which at least half the voters prefer a harder Brexit, and at least half favour a softer Brexit. The claim that this system is truthful, is based on the presumed single-peaked-ness of preferences: every voter has a favourite option, and their support for the others goes down, the further away you get from the favoured option.
Of course, the only thing less likely than a second referendum is the adoption of an eminently sensible approach such as the one above, and the interesting question is, why it would not be used. One objection I can think of, goes as follows: suppose there are 3 alternatives offered, say Norway plus, Theresa May’s deal, and no-deal. Suppose that 20 million voters support Norway plus, another 20 million support no-deal, and one voter supports May’s deal. In that case, May’s deal wins, and someone would complain it’s (a lot) less popular than one of the others (probably the one the complainant supported). In reality, this result should have everyone — on both sides — celebrating the fact that whatever outcome they liked least has just been narrowly averted. A better objection is that some people would prefer a principled in-or-out result, and either extreme is preferable to some sort of fudge. (I admit, I recently heard that view sincerely expressed.) So, for them the vote is not truthful, but there are not many people like that, and they are free to vote (strategically) for whatever extreme they prefer. A third objection, implicit in most objections to electoral reform, states that voters are too stupid to understand anything other than plurality, or “first past the post”.
If the above system were used in Parliament, May’s deal would probably win, unless MPs were allowed to vote anonymously, in which case Norway Plus would probably win.
I checked the paper Thirteen Reasons Why the Vickrey-Clarke-Groves Process Is Not Practical since the point about voting is analogous to the observation that no-one uses VCG. The 13 reasons are mostly not applicable, or only weakly applicable, to the above election. It is true that there are other weak equilibria besides truth-telling, but it seems unlikely that someone would vote against his preference simply because he’s unlikely to swing the outcome.
The effort we put into studying voting systems is justified by the following Milton Friedman quote:
Of course, the only thing less likely than a second referendum is the adoption of an eminently sensible approach such as the one above, and the interesting question is, why it would not be used. One objection I can think of, goes as follows: suppose there are 3 alternatives offered, say Norway plus, Theresa May’s deal, and no-deal. Suppose that 20 million voters support Norway plus, another 20 million support no-deal, and one voter supports May’s deal. In that case, May’s deal wins, and someone would complain it’s (a lot) less popular than one of the others (probably the one the complainant supported). In reality, this result should have everyone — on both sides — celebrating the fact that whatever outcome they liked least has just been narrowly averted. A better objection is that some people would prefer a principled in-or-out result, and either extreme is preferable to some sort of fudge. (I admit, I recently heard that view sincerely expressed.) So, for them the vote is not truthful, but there are not many people like that, and they are free to vote (strategically) for whatever extreme they prefer. A third objection, implicit in most objections to electoral reform, states that voters are too stupid to understand anything other than plurality, or “first past the post”.
If the above system were used in Parliament, May’s deal would probably win, unless MPs were allowed to vote anonymously, in which case Norway Plus would probably win.
I checked the paper Thirteen Reasons Why the Vickrey-Clarke-Groves Process Is Not Practical since the point about voting is analogous to the observation that no-one uses VCG. The 13 reasons are mostly not applicable, or only weakly applicable, to the above election. It is true that there are other weak equilibria besides truth-telling, but it seems unlikely that someone would vote against his preference simply because he’s unlikely to swing the outcome.
The effort we put into studying voting systems is justified by the following Milton Friedman quote:
Only a crisis - actual or perceived - produces real change. When that crisis occurs, the actions that are taken depend on the ideas that are lying around. That, I believe, is our basic function: to develop alternatives to existing policies, to keep them alive and available until the politically impossible becomes the politically inevitable.
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