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Faculty of Economics

Monday, 25 March, 2019

We very much welcome the announcements over the past few days that Parliament is set this coming week to hold sequence of indicative votes on the form of EU Exit. It has been over 1,000 days since the Referendum and much has been learnt about the consequences of different forms of EU Exit. And so before any form of Exit is agreed it makes considerable sense to learn whether one form of Exit would command a majority from an informed Parliament. It is though critical that this process is conclusive, fair to all options, and accounts for the incentives driving Parliamentarians’ votes. In the Commentary of the February 2019 National Institute Economic Review no 247, NIESR’s Director Jagjit Chadha together with the University of Cambridge’s Dr Toke Aidt and Professor Hamid Sabourian, both of the Faculty of Economics, suggested a way out of the Brexit vote impasse, based on game theory and the social choice literature.

They reject the mantra that the failure of the recent “meaningful votes” in Parliament means that no majority can be found for any proposal. They state that an alternative is favoured by a majority if there is no other plan that can win a majority vote against it. Such an alternative is called the Condorcet Winner (after 18th century philosopher and mathematician the Marquis de Condorcet). They argue that the Condorcet Winner is likely to exist and that it is possible to design a fair and democratically legitimate voting procedure in Parliament that results in the Condorcet winner being chosen even in a situation with multiple alternatives. The important feature of their design is that the Parliament is asked to compare all alternatives and that a sequential run-off, or weakest link procedure, is adopted so that we end up with a winner favoured by the majority. A single vote or one that involves a simultaneous set of binary choices simply will not work.

Prof Sabourian said: “Democratic legitimacy require three clear considerations in the vote process. First, any alternative that commands some support from some group must be on the agenda. This is the open agenda principle. Secondly, any alternative should be treated in the same way and not arbitrarily put into competition against the status quo or some random other alternative. This is the neutrality principle that ensures fairness and means that the voting procedure does not itself bias the final choice. Violating neutrality would expose the procedure to the accusation that the process was rigged in some way. Third, if there is an alternative that is the Condorcet winner, the voting procedure must ensure that it is elected.”

Prof Chadha said: “When faced with multiple Exit options asking for a sequence of binary ballots in favour or against each plan, may cause paralysis because every plan may be rejected as in the Lords Reform vote of 2003. And this may occur even though there may be an alternative that is favoured by a majority - Condorcet Winner. Effectively, each ballot would be a vote on a given proposal against ‘not that proposal’. For example, if there were three alternatives, A, B and C, then a ballot on A would in effect be a ballot on A against either B or C. And in the case of Brexit, ‘not that proposal’ is a bundle of many, many different options including an ill-defined status quo which would not allow us to decide our next step at this critical moment in the nation’s history.”

Should Parliament be called upon to express its preference on a set of alternatives (the Government’s deal, WTO Brexit, Norway++, Canada++, Remain, a new referendum and so on) Dr Aidt and Professors Chadha and Sabourian propose a multi-round voting procedure, dubbed ‘The Weakest Link’, in which in each round the MPs would vote between all remaining alternatives and the one with the least votes would be eliminated. Voting should continue until only one alternative is left. This procedure builds on an open agenda by considering all options, satisfies the principle of neutrality, and if a majority winner exists will deliver a genuine majority winner in the highly likely case that MPs will be voting strategically. A variant of this procedure is explored in the Review paper that deals with the case where MPs act in both strategic and sincere manners and this would involve ranking across alternatives at every round of the vote.

Dr Aidt concludes: “We believe that there is a strong case for adopting our procedure to resolve the Brexit impasse in the House of Commons. It would have to be undertaken in a sequence of indicative votes that would end with a binding vote between the two last alternatives. With more than two alternatives and strategic voting, standard one-shot voting procedures, such as first past the post (plurality) or single transferrable voting, cannot ensure that the alternative that is favoured by a majority is chosen.”

“Breaking the Brexit impasse: achieving a fair, legitimate and democratic outcome” was published in the National Institute Economic Review No. 247 February 2019.

Related links:

How to Find Out What MPs Really Want - Prospect Magazine
Breaking the Brexit impasse - VOXeu
Breaking the Brexit impasse: achieving a fair, legitimate and democratic outcome - National Institute Economic Review

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