Political scientists have become increasingly preoccupied with the relentless (0) POLARISATION (POLAR) of debate in mature democracies. Where voters once clustered around a crowded centre, the public now divides into camps whose 1IDEOLOGY commitments appear to harden with every passing election cycle. Self-described 2MODERATE, once the reliable arbiters of close contests, report that they feel politically homeless, squeezed out by activists on either flank. The 3RESENT that fuels this realignment is stoked less by policy disagreement than by a sense that one's values are held in contempt by the other side. Issues that were long treated as settled have become freshly 4CONTROVERSY, and the carefully negotiated 5COMPROMISE of an earlier era are increasingly recast as betrayals. Social media rewards 6RHETORIC escalation over substantive argument, and politicians have every incentive to oblige. The consequences for democratic 7GOVERN are troubling, since effective policymaking presupposes at least a minimal willingness to deal with one's opponents. In such a climate, opportunistic 8DEMAGOGUE find a readier audience than they have enjoyed in decades.