Should a referendum need more than half the votes to win?

Whether a referendum should need more than half the votes is a real disagreement, and different places have answered it differently. The usual rule is a simple majority, one-half of the votes, sometimes written "50% plus 1 vote". A supermajority asks for more. Supporters say such rules can stop a bare majority from eroding a minority's fundamental rights. Critics say they can hamper efforts to respond to problems and encourage corrupt compromises.

Montenegro in 2006 is a well-known example of a high bar. Its government, which backed independence, first advocated a simple majority, but the opposition insisted on a threshold below which a Yes win would be moot. An EU envoy, Miroslav Lajčák, proposed that independence would need a 55 percent supermajority of the votes cast and a minimum turnout of 50 percent. The pro-independence side protested, but the government ultimately backed down in its opposition. On 21 May 2006, 55.5 percent voted Yes, narrowly passing the threshold: only about 2,000 votes were over it, the votes of two or three polling stations.

A second kind of bar is a turnout rule. In Scotland's 1979 devolution referendum, 51.6 percent voted Yes, but an amendment said the Act would be repealed unless Yes votes reached 40 percent of the whole electorate. With a turnout of 64 percent, Yes was only 32.9 percent of the registered electorate, and the Act was repealed.

Canada has argued about the same question for secession votes. Quebec's Bill 99 declares the winning majority to be 50 percent plus 1 vote, while Stéphane Dion argued that a simple majority that could disappear in the face of difficulties would not be enough for political legitimacy. The fight is about what level of support makes a result legitimate.