A referendum presents a different set of choices than does an election. No political parties or candidate names appear on the ballot, and voters must choose among alternatives that are sometimes unfamiliar and perhaps lacking in partisan cues. One might therefore expect a greater degree of volatility and uncertainty in referendum voting than is typically found in elections. Particularly in those instances where the issue(s) of the referendum are new to the voter, the campaign dynamic which ensues becomes critical to the determination of the outcome. Only through the various information sources available to them over the course of a campaign will voters be able to form opinions on new and unfamiliar (or only partly familiar) ballot questions. As Bützer and Marquis show in Chapter 10, this process of opinion formation is of primary importance for the wide variety of issues which Swiss voters are routinely asked to consider. Applying Zaller's (1992) model of communication flows, they show that information communicated by elites during the course of a referendum campaign is often crucial to the outcome of a vote on an issue about which voters may have little prior information. This view is also supported by evidence from US studies (Lupia 1994; Bowler and Donovan 1998; Lupia and McCubbins 1998). Voters draw upon a variety of sources in forming opinions about the sometimes complex and confusing initiatives which routinely appear on many US state ballots. 1 Among the most frequently mentioned sources of such information are campaign pamphlets, newspaper and television editorials, and direct mailings from campaign organizations. Voters take their cues from these and other campaign sources, as well as from individuals, groups and organizations with which they identify.
In other situations, however, voters may be able to make up their minds much more quickly on the basis of partisan or ideological perceptions, or familiarity with one or more positions in a long-standing political debate. Strong supporters of the Parti québécois, for example, would hardly have needed a campaign in order to make up their minds how to vote in the 1995 Quebec sovereignty referendum, given that the 'sovereignty' issue has been debated for more than twenty years and itself forms the basis on which the party system in Quebec is aligned. Referendums such as the 1980 vote