In recent years, volatility in the electoral fortunes of major political parties in Western democracies has invigorated scholarly debate over the roles that parties play in the political process and the positions that they occupy in the public mind. Data from national election surveys and inter-election public opinion polls reveal that parties have declined in the minds of citizens in the United States, Canada, and Great Britain over the past 40 years. Varying combinations of decreasing percentages of strong party identifiers, increasing percentages of independents and nonidentifiers, and increasing individual-level instability in party identifications indicate that the electorates of all three countries have experienced significant “dealignments of degree.” The three cases are not atypical; survey evidence indicates that partisan attachments have weakened in a wide variety of mature democracies.