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.