According to well-established research, voting behaviour is dependent on both long-term (social cleavages, party identification and value priorities) and short-term (issues, namely economic issues, candidate evaluations and other specific social and political events) effects. Since the late 1970s, the impact of long term effects on voting behaviour are said to be in decline (Dalton, Flanagan and. Beck, 1984; Flanagan e Dalton, 1985; Franklin et al, 1992; Inglehart, 1990 and 1997; Dalton and Wattenberg, 2000). In the context of cleavage voting decline, increased attention has been given to the short term effects on voting behaviour, especially economic voting (Kiewiet, 1983; Lewis-Beck, 1988; Norporth et al, 1991; Anderson, 1995; Electoral Studies 2000/Special issue on economic voting), following a rational actor model (Downs, 1957) as opposed to, or complementing the so-called cleavage model (Lipset and Rokkan, 1967). <p>Applying the economic voting methodology to West European party systems can be problematic because of the existence of multiparty systems and government coalitions. For instance, in a three-party system with a two-party incumbent coalition, the disgruntled voter may defect from one coalition party to another. Thus, three main conditions must be met for it to be possible: firstly, the electorate must be able to identify and hold the incumbent responsible for the performance of the economy; secondly, the electorate must be able to cast a vote for the opposition which has a real chance to achieve power; thirdly, the ideological distance between parties must be small enough to allow each of them to be a credible voting alternative (Bellucci, 1984: 390).</p><p>One of the distinguishing features of the economic vote function is its instability (Lewis-Beck and Paldam, 2000). This may be due to a number of factors namely, a very strong anchor of partisanship on cleavages (social and/or ideological); asymmetric impact of economic perceptions on the vote, i.e., being significant only in negative economic conditions; and the misspecification of the voting model, namely in terms of the political context, etc. (Lewis-Beck, 1988; Powell e Whitten, 1993; Anderson, 1995 and 2000; Lewis-Beck and Paldam, 2000).&nbsp; </p><p>Clarity of responsibility is higher in those situations where only one party controls government and has majority support in parliament. In these conditions economic voting should be very strong, ceteris paribus. On the contrary, in coalition government situations it might not be so clear for the voter who can be blamed for economic management. In these situations, economic voting is not expected to be very strong, especially when all government parties are considered (Anderson, 1995 and 2000). An intermediate situation takes place when there is a minority single-party government.&nbsp; In these conditions, the government party must negotiate with other parties all policy proposals, namely the budget, so that they can be successfully passed in parliament. Naturally, there are other political features that matter in terms of clarity of responsibility, namely bicameralism and dual executive structures (Powell e Whitten, 1993; Lewis-Beck and Nadeau, 2000). </p><p>Together, Spain, Greece and Portugal produced five of the eight most volatile elections between 1945 and 2000 (Gunther and Montero, 2001:88).&nbsp; This is already an indicator that social and ideological anchors of partisanship are not very strong, especially in the Greek and Portuguese cases where a great amount of electoral volatility is inter-bloc (about types of volatility, see Bartolini and Mair, 1990; about levels of volatility in these countries in a comparative context, see Gunther and Montero, 2001; Lobo, 1996; Freire, 2001a). </p><p>In these conditions these three countries can be said to be special test cases for evaluating the relative impact of cleavages and economic short-term effects on voting behaviour. Gunther and Montero (2001) showed that short-term effects are indeed very important, but the authors only tested the impact of party leadership evaluations on the vote. Thus, the test of the relative impact of cleavages and the economy on the vote is still to be done, especially in a comparative perspective.&nbsp; </p>