Democracies are fragile. No matter how long a regime has been democratic, it is always confronted with the possibility of becoming dysfunctional, of becoming less democratic, and possibly breaking down. Some scholars believe that polarisation is the single most important cause of the failure of democracy, because if there is too much disagreement the political system cannot possibly work. Others argue that without polarisation, parties fail to provide the voters with viable alternatives and, by doing so, undermine the quality of democracy. So how much disagreement is too much?