Rarely has a policy debate so divided and paralyzed a nation as the issue of “Brexit” in the United Kingdom. In a 2016 national referendum, British voters narrowly approved leaving the European Union. The aftermath and turmoil ever since provides a case study in how such divisions are poorly handled by a plurality, single-choice voting system -- yes, the same voting method used by Americans to elect their members of Congress, governors and presidential electors.
One problem is being able to win a majority of seats without trying to win a majority of votes. Since 1980, no British political party has won even 44% of the national vote. In 2015, for example, David Cameron’s Conservative Party won a majority of seats with only 36.9% of the votes. His plurality victory was reminiscent of Bill Clinton winning a huge majority of electoral votes in 1992 with only 43% of the vote (and only a single state with more than 50%) and, more recently, Justin Trudeau of Canada's Liberal Party maintaining power with only 33% of the vote, less than the Conservative Party.
Now, Boris Johnson leads the Conservatives, and his bid is all about playing to the “leave” Brexit base rather than a majority of Britons. “Remain” now consistently leads in polls, but its backers are divided among several parties. Johnson received a boost this week when Nigel Farage’s Brexit Party announced it would try to avoid splitting the “leave” vote by not running candidates in any seats now held by Conservatives. Farage is a long-time critic of plurality voting, and his party earlier this year joined a cross-party reform coalition in support of a proportional voting system. But Farage also knows that, in a plurality system, a more united “leave” vote provides the best chance for Johnson to turn 40% of the vote into a majority of seats.