Referenda are important instruments of democratic politics. They have been used since the late eighteenth century in various circumstances of political life, most often in relation to constitutional change or issues of self-determination. In contemporary democratic societies, there is pressure to submit contested political questions to popular vote, in order to reduce tensions between popular will and governance. Even democratic governments which are not constitutionally obliged to do so now feel compelled to consult the people directly. 

Brexit, the UK’s referendum on whether to stay in the EU, reflects this tendency. It is not the first referendum on EU matters. And yet, there is novelty here: the people were deciding directly whether to leave an organization of democratic states, …