Political parties are the most important organizations in modern politics, and only a small percentage of states do without them. Students of political parties have commonly associated them with democracy itself. David Robertson, for example, observes that 'to talk, today, about democracy, is to talk about a system of competitive political parties. Unless one chooses to reject the representative model that has been the staple of the theory and practice of democracy since the French Revolution, one must come to terms with political parties' (Robertson 1976 : 1). Much the same point is made by G. Bingham Powell: 'the competitive electoral context, with several political parties organizing the alternatives that face the voters, is the identifying property of the contemporary democratic process' (Powell 1982 : 3). Thus, representative democracy has long been associated with, or even equated with, party government.
The vast scholarly literature on political parties reflects their real-life importance and has developed along with them. The twentieth century has been the century of political parties. At least, that was clearly the trend well beyond the first half of the century. The early days of the twentieth century saw the breakthrough of political parties as the democratic organization par excellence. Parties attained this position both because they were unrivalled in their functions of 'linkage' (Lawson 1980 ; Lawson and Merkl 1988), 'expression', or 'channelment' (Sartori 1976) and, in particular, because they were the vehicles of previously unenfranchised groups such as workers and peasants. Since the late 1960s, however, doubts have grown concerning the power, functions, and even necessity of political parties, as previous chapters in this volume have pointed out.
Political parties have many facets. They originated as more or less formally organized groups of public office-holders, and this in all likelihood is the arena in which their influence has persisted most comfortably. And although parties have roots in society, they are shaped by the political institutions in which they operate.