Real-world trends, public issue salience, and electoral results in Europe

Europe has experienced several marked, cross-national trends in electoral results in the 21st century, which scholars have explained using social structure and challenger party entrepreneurship. We propose a third theoretical explanation: (1) electoral outcomes have resulted from marked changes in what issues Europeans perceive as the most important affecting their countries; and (2) the latter have been determined by “real-world” societal developments, in addition to a changing party system issue agenda. We use panel data across 28 European countries to show that the public issue salience of three issues—unemployment, immigration, and the environment—explains variation in the results of the conservative, social democrat, liberal, radical right, radical left, and green party families in line with theoretical expectations, while the party system issue agenda has weaker effects. We also show that the public salience of these issues is rooted in unemployment rates, immigration rates and temperature anomalies, and party agenda-setting; and that the party system issue agenda follows public issue salience but not our societal trends. We validate our mechanism at the individual-level across 28 European countries and again using panel data. Our findings have implications for our understanding of the agency of parties, the permanency of recent electoral changes, and how voters reconcile their social and political worlds.


Introduction
Europe has experienced several marked, cross-national trends in electoral results during the 21st century, including growing vote shares for radical right, radical left, and, latterly, green parties and declining vote shares for social democrat, and, less emphatically, conservative, and liberal parties.In this article we offer a novel explanation for these cross-country electoral trends.Existing explanations broadly draw on two theoretical approaches: cleavage theory, which emphasises the role of longterm socio-structural transformations affecting policy attitudes and voter links with parties; and party entrepreneurship, with which emphasizes political actors strategically affecting the issue agenda to their own advantage.We propose that electoral outcomes have resulted from marked changes in what Europeans perceive as the most important issues affecting their countries, which are determined by "real-world" societal developments in addition to party agenda-setting.As such, our explanatory approach is distinctive and complementary to the others in that it is based on changing issue salience but sees this in primarily bottom-up, societal terms.
We use national-level and individual-level panel data to explain voting for six party familiesconservative, social democrat, liberal, radical right, radical left, and green-across 28 European countries at both the national-and individual-level.At the national-level we augment Eurobarometer data with data from the Manifesto Project Database, Eurostat, and the Global Historical Climatology Network, at the individual-level we use European Election Study augmented with Chapel Hill Expert Survey data and British Election Study panel data, and we support our claims with evidence from the European Social Survey and European Values Study.We show that the public salience of immigration increases the vote share of the radical right and reduces that of conservative, social democrat, and radical left parties.Similarly, the public salience of unemployment increases the vote share of the radical left and social democrats and reduces that of radical right and green parties; and the public salience of the environment increases the vote share of the greens and reduces that of the social democrats and radical left.In turn, we show that the public salience of each of those issues is driven by short-term societal trends-immigration and unemployment rates and temperature anomaliesas well as, to a lesser extent, agenda-setting.We also find that the party system issue agenda, which has mixed effects on party family vote share, is partially set by public issue salience but not by our societal trends.
We therefore argue that the agency of parties to set the terms of the political debate to their own advantage is limited, and instead they are forced to chase the issues that voters decide are important.As such, democratic politics is driven by forces exogenous to it, with longer-term sociostructural changes episodically manifested in shorter-term, newsworthy, and vote-shifting events.As exogenous trends and events are becoming more transnational, domestic party competition across countries is becoming subject to trends that are increasingly synchronous, as has happened in Europe, further highlighting the limits placed on largely domestically focused political entrepreneurs.Finally, whereas party systems and public attitudes are formed by long-term socio-structural forces and resultant social groups, shorter-term volatility is likely to result from considerations over the most important issues of the day, so that the political person's shorter term cognitive and behavioural reconciling of the political and social worlds is primarily dictated by prioritisation.More substantively, our theoretical approach also sees recent electoral transformations to be potentially fleeting, with the public's issue agenda having the potential to change in a way that no longer benefits the respective non-mainstream parties, notwithstanding longer-term structural changes to their potential vote share.Finally, in our discussion we consider the challenges of this approach, particularly the complexities of measuring short-term, "real-world" societal trends in a theoretically grounded way that recognises the role of the media as mediators and supply-side considerations, not least regarding how parties fight to "ride the waves" and claim ownership of public concern.

Existing explanations for Europe's changing electoral landscape
The starkness and novelty of recent electoral trends in Europe have prompted significant academic enquiry, which we argue can be imperfectly divided into two theoretical camps.The first strand of explanations sees electoral change as the outcome of long-term socio-structural transformations.These approaches are generally based on the assumptions of cleavage theory (Lipset and Rokkan, 1967), according to which party systems reflect conflicting interests amongst social groups and remain rigid until disrupted by rare "critical junctures" (for review see von Schoultz, 2016).In this theoretical vein, parties have minimal agency over the forces determining long-term trends in electoral results and are, rather, the political manifestation and representation of those forces.Numerous scholars have utilised this theoretical approach to explain recent changes in Europe.Hutter and Kriesi (2019) (see also, e.g., Kriesi et al, 2006Kriesi et al, , 2012;;Dalton, 2018;Hooghe and Marks, 2017) have argued that long-term social transformations resulting from globalisation are reshaping European party systems by 'opposing those who benefit from this process against those who tend to lose' (Kriesi et al. 2006: 921), with the "losers" turning to the radical right and "winners" turning to the greens, who had already been conceptualised as beneficiaries of earlier social transformations including the "silent revolution" towards post-material values and the related expansion of higher education (Inglehart, 1977;Kitschelt, 1990).Hooghe and Marks (2017: 17) focus less on long-term socio-structural forces and more on the short-term effects of the Eurozone crises and the "migration crisis" on raising the salience of the 'transnational cleavage', still determined by the 'winners' and 'losers' of globalisation.Notably, in each of these accounts, salience is conceptualised and measured as the emphasis that parties, rather than voters, place on issues.
Several party-specific explanations for electoral trends have also taken a socio-structural approach, without the assumptions of cleavage theory.The decline of social democratic parties has been explained by the decline of the traditional working class, de-industrialisation and 'embourgeoisement' (Benedetto et al, 2020;Gingrich and Häusermann, 2015) and attitudinal divides between middle-class and working-class centre-left voters (Abou-Chadi andWagner, 2019, 2020;Keating and McCrone, 2013).Accounts for the rise of the radical right have similarly focused on either economic competition or cultural threat deriving from increasing immigration to Western Europe and globalisation (e.g.Inglehart and Norris, 2019; for a review, see Arzheimer, 2018).Whereas the electoral growth of green parties has been argued to result from value change and educational expansion, increased radical left success has also been interpreted in socio-structural terms attributing it to the support by the "losers of globalisation", the north-south divide within the Eurozone, unemployment, and antiglobalisation attitudes (March and Rommerskirchen, 2015;Visser et al, 2014).
The second strand of explanations sees electoral change as the result of shorter-term party entrepreneurship.Notably, de Vries and Hobolt (2020: 6;2015) argue that oligopolies of 'dominant' parties, subject to decreasing voter loyalty, have been under 'attack' by challenger parties, who challenge by 'introducing issues that can drive a wedge between coalitions' and using antiestablishment rhetoric.Similarly, Green-Pedersen (2019) explains party system change via new issues that are, in his view, determined by the strategic considerations of political parties.The key assumptions of these approaches are that parties have a high degree of agency over what issues are considered important to the public, in direct contrast to the passive conceptualisation of cleavage theoretical approaches.According to this approach, disruptive, challenger parties have introduced political issues that are new or ignored by mainstream parties-such as immigration, the environment and, in southern Europe, unemployment-leading to greater interest in those issues among the voters, who change their voting behaviour accordingly.In addition to these issue ownership modelinspired accounts, there exist other party-centric or "supply-side" accounts for recent changes, such as those focussing on social democratic parties ideologically moving to the centre (Rennwald and Evans, 2014;Escalona and Vieira, 2014); and explanations focusing on centre-left parties being 'squeezed' by radical left, green and radical right parties (Cuperus, 2018).

Our theoretical approach
Our distinct yet complementary proposition is based on several theoretical assumptions.First, we assume that citizens vote both in sociotropic terms-that is, in terms of what they see as in the best interests of their country (and, thus, the most important issues affecting it)-as well as selfinterested terms (see Wang, 2017, for review).Second, whereas party systems and public attitudes are formed by long-term socio-structural forces and resultant social groups, shorter-term volatility in vote choice is more likely to result from cognitive considerations over the most important issues of the day.However, although attitudinal considerations are the most powerful when explaining between-individual variation in party choice, the stability of such attitudinal positions (see Kustov et al, 2021;Hooghe and Wilkenfeld, 2008; and our analyses below)-a result of their formation by early life socialisation and deep-seated psychological predispositions-makes them less well-suited to predict rapid variation in electoral outcomes over time.
Third, political parties are constrained in their ability to set the agenda and are forced to follow the voters-'Parties respond to voters, but voters do not necessarily respond to parties' (Klüver and Spoon, 2016: 663; see also, Spoon and Klüver, 2014;Gentzkow and Shapiro, 2010;Stimson, 2004).Similarly, fourth, public issue salience is determined by exogenous events and trends independently of political and media cues (Singer, 2011;Klüver and Sagarzazu, 2015;McAllister and bin Oslan, 2021;Dennison, 2020;Gilardi et al, 2021), with the latter able to mediate the effects of exogenous social trends and events but limited in their selection of what issues to cover.Indeed, the recent cross-national nature of trends in public issue salience in Europe suggests that their determinants are ultimately exogenous to divergent domestic party or media agenda-setting capabilities.
Crucially, this requires distinguishing between two types of social phenomena: (1) medium-and long-term, slow-moving structural trends that fundamentally affect the very basis and assumptions of society and its cleavages, but less acutely form part of the political conversation, such as changing climatic or economic patterns, and (2) short-term social trends and events that become of public interest due to their relative and perceived uncertainty, risk, novelty, and need to be immediately resolved (Dennison, 2021), such as natural disasters and economic or migratory crises.Overall, in line with recent findings, we see agenda-setting as 'largely exogenous to both parties and media' (Gilardi et al, 2021), although not entirely so.
Fifth, on the supply-side, parties compete over being seen as the most competent in dealing with the issues of the day.The outcome of this competition is primarily determined by governing party performance evaluations (e.g.Craig and Cossette, 2020) and perceived intra-party unity (Greene and Haber, 2015) rather than by opposition or challenger party activity.However, long-term prioritisation of an issue also leads to association with an issue, from which party families like the radical right, radical left, and greens are particularly likely to benefit (Walgrave et al, 2015, for review).Indeed, recent electoral changes in Europe have often been preceded by the perceived loss of competence of multiple mainstream parties on a salient issue followed by the rise of new challenger parties that have the benefit of appearing internally united on what is their primary issue.Overall, 'party competition plays out more by what politicians actually do and what impression they give about their deeds and competence than by exercising influence on the issue agenda' (Meyer and Müller, 2013).
We posit that public issue salience is both rooted in long-term structural transformations and subject to short-term variation when, for example, the long-term trends become particularly visible or obviously in need of political resolution.Such situations may transpire more regularly as the underlying structural change deepens or remains unresolved.Furthermore, issue salience is typically measured in a relative and ordinal ("most important"), rather than absolute, manner; the salience of an issue therefore varies relative to other issues, reflecting psychological findings on the tendency of humans to prioritise only a few issues at a time (Boninger et al, 1995;Dennison, 2019).As such, high volatility in relative salience, as measured by the "most important issue/problem" questions", likely hides steadier long-term trends in the absolute perceived salience of an issue.Finally, short-term variation in issue salience may have long-term consequences for party preferences via the breaking and creating of voting habits (Shachar, 2003;Achen and Bartels, 2016).
In this sense, our approach is akin to the original assumptions of both issue voting and cleavage theory.Regarding issue voting, as Budge (2015: 766) stated, 'election issues appeared as the result of external developments rather than party manipulation.Parties might try to emphasise favourable issues to suit prevailing circumstances.But the latter dictated the agenda'.Regarding cleavage theory, Lipset and Rokkan (1967: 94) observed that short-term variation in electoral results from a 'hierarchy of cleavage bases' according to their relative 'political weight' as determined by socioeconomic trends and events exogenous to the party system rather than social or political cues (see also Ansolabehere and Iyengar, 1994;Sides, 2006).
We do not argue that parties have no agency over public issue salience (e.g.Green-Pedersen and Mortensen, 2010), but instead that such agency is constrained by external developments and the need to be seen to respond to them, which they do by pursuing association with an issue and underlining their own competence-and the mainstream parties' lack of it.Similarly, compared to the longer-term explanatory power of extant cleavage theoretical approaches, the rapidity of trends visible in Figure 2, such as over 80 per cent of Germans listing immigration as the most important issue affecting their country in 2016, up from less than 10 per cent two years earlier, or similar trends for unemployment in Spain and recently the environment in Greece, highlight the insufficiency of only cleavage theoretical approaches.Our theoretical proposition is visualised in Figure 1, though can be summarised by the response of British Prime Minister Harold Macmillan in 1957 when asked about the major challenges to his government: "events, dear boy, events".

Methods and data
We test our theoretical approach in five steps.First, we demonstrate change over time across Europe in the public issue salience of three issues-immigration, unemployment, and the environmentand in the distribution of policy preferences to those three issues.Second, we test the effects of immigration rates, temperature anomalies and unemployment rates and the party system issue agenda on the public issue salience of those three issues respectively.Third, in turn, we test the effects of the three societal trends and public issue salience on the party system issue agenda of the respective three issues.Fourth, we test the effects of both the public salience of those issues and their role in the party system issue agenda on electoral support for six party families across Europe.Fifth, we test the effects of public issue salience and policy attitudes to those issues-bringing in spatial considerations-at the individual-level using cross sectional data across the EU28 and using panel data in the United Kingdom.
Data for public issue salience is taken from the Eurobarometer.Since 2005, the Eurobarometer survey has asked a representative sample of every country in the European Union "what do you think are the two most important issues affecting your country?"Respondents are offered around 14 responses, which have changed occasionally over time.We choose three issues because they stand out both for the scale of their change and the cross-national trends in their variation: immigration, unemployment, and the environment.'The economy' was also highly salient throughout this period, but largely tracked unemployment, while trends in crime, debt, education, health, housing, inflation, tax, terrorism, and pensions were less intense and inconsistent across countries.The three issues are regularly respectively associated with the radical right, radical left, and greens parties.
Our policy attitudinal data for the same three issues are taken from the European Social Survey (ESS) and the European Values Study (EVS).We measure attitudes to immigration with a factor variable based on the six immigration items in the ESS of 2002/3 and 2018/9.Regarding unemployment, we use the ESS's single question on the topic asked in 2008 and 2016: 'To what extent do you think it is the responsibility of the government to ensure a reasonable standard of living for the unemployed?', with respondents given an eleven-point scale.Finally, regarding attitudes to the environment, there are numerous sources of data measuring, for example, belief in climate change, the priority that the environment protection should be given vis-à-vis economic growth, etc.We choose a question that relates most closely to the previous policy questions: "To what extent do you agree that 'I would give part of my income if I were certain that the money would be used to prevent environmental pollution'" as taken from the EVS in 2008/9 and 2018/19.
For societal trends, we use immigration rates, temperature anomalies and unemployment rates.Although other societal trends, such as irregular immigration rates or flooding, may make alternative or even more powerful predictors of the salience of these issues, we choose the theoretically broadest possible metrics (see also McAllister and bin Oslan, 2021;Hoffmann et al, 2022).Immigration rates are measured using Eurostat data from 2007 to 2018 on new immigrants per year, which is then divided by population size.The mean is 0.0098 and the standard deviation is 0.0089, so that, on average, for every 100 citizens in an EU member state, almost one new immigrant arrived per year during the period.Monthly unemployment rates are also obtained from Eurostat starting in 2005, with a mean of 8.57 and a standard deviation of 4.47.We produce values of temperature anomalies using Global Historical Climatology Network (GHCN, 2019) data and calculated as that month's deviation from the mean surface temperature in each country's capital city in the respective month over the period 1960 to 2004.The largest differential is 7.0° in November 2011 in Poland, which had a temperature that month of 5.4° and a mean temperature during the reference period of the Novembers between 1960 to 2004 of -1.7°.The mean is 1.49 and the standard deviation in 1.29, so that, on average, each EU member state was 1.49 degrees hotter during the time series than their respective average during the period 1960 to 2004.
To capture agenda-setting we create a variable for the party system issue agenda -the emphasis given to an issue across the entire party system (Green-Pedersen and Mortensen, 2010).The party system agenda connects the issue emphasis of individual parties and emerges from the continuous political debate among political parties, allowing us to capture the overall agenda-setting capacity of the party system on a single issue.Our party system issue agenda data comes from the Manifesto Project Dataset (Volkens et al, 2021) which includes the emphasis-measured as mentions-that each party gave to various political issues in the most recent election manifesto in most EU and OECD (and beyond) countries, going back to the mid twentieth century.We create an indicator corresponding to the weighted sum of the manifesto scores for every party at the most recent election preceding the respective Eurobarometer surveys, where each party is weighted by its vote share, resulting in three respective party system issue agenda indicators1 per country.
We use fixed effects panel data models to test our theoretical framework.Such models test only the effects of within-country or -individual variation in the explanatory predictors on the within-country or -individual variation in the dependent variable.As such, all unobserved time-invariant betweencountry or -individual effects are controlled for.At the national level this includes, for example, the historic issue agenda or party system and more distal predictors, like economic, demographic, political (e.g. the electoral system), and social factors.At the individual-level they include (typically) gender and other socio-demographics, pre-adulthood socialization, and psychological predispositions.
We use these models at the national level in three ways: first, we test how societal trends and the party system issue agenda affect public issue salience; second, how societal trends and public issue salience affect the party system issue agenda; and, third, how public issue salience and the party system issue agenda affects party family vote share.The second set of models have a far lower number of observations because there are fewer elections per country than Eurobarometer waves during the period; for these we use the two independent variables from the previous wave to ensure correct temporal ordering.The sources of vote shares-both from electoral results and opinion polling-for each member state from 2005 to 2019 are outlined in Appendix 1.We take opinion polls on vote intentions just from those months in which the Eurobarometer was surveyed, producing an average of all opinion polls in that country in the respective month unless there is a parliamentary election that month, in which case we use the results of the election (in France we use the first round of the presidential election).The party family classification follows the ParlGov classification of parties into party families (Döring and Manow 2019).
We validate the mechanism at the individual-level by testing whether public issue salience predicts vote switching when spatial considerations are incorporated using two separate data sources.First, we use European Election Study (EES) data and logistic models to predict vote switching in the next national general election to each of the respective six parties, by considering vote intentions for each party amongst those who did not vote for them at the previous general election.The 2014 European Election Study (EES) voters survey (Schmitt et al, 2016) included representative samples in all then 28 EU member states.It asked respondents about: their previous vote choice in national elections and how they would vote if there were an upcoming election; what they consider to be the most and the second important issue affecting their country; several policy attitudes on a 0-10 scale (immigration policy, prioritizing environmental protection over growth; and state intervention in the economy).For the sake of party classification, we use the 2014 Chapel Hill Expert Survey (Polk et al, 2017) because it can be linked to the EES.Those countries that do not have one of the respective parties are removed from the respective model.Second, we use the British Election Study (BES) 2014-2021 panel study (Fieldhouse et al, 2021) to produce fixed effects logistic panel models of vote intentions for each party family (except for the radical left, which has no meaningful representation in the UK).Our dependent variable asks individuals for whom they would vote if there were an election tomorrow, except in those waves that just followed a general election in which case they are asked whom they just voted for.The estimator is logistic, owing to the binary response variable.The study asks respondents what they think is the most important issue affecting their country, with the open-ended responses of the first 13 waves of the study (up until June 2017) having been categorised and used in our analyses.For policy questions, we use a factor variable made from three questions measuring attitudes to immigration, a question on belief that 'measures to protect the environment' have gone too far, and a question on belief that it is not one's own fault if one is unemployed.

Changing levels of issue salience, distributions of policy attitudes, and party family electoral support
In Figure 2, we plot the changing public issue salience of the three issues by EU member state from 2005 to 2019.We group the member states largely along regional lines-north-western Europe, southern Europe, and central and eastern Europe.In all three regions, the sequence of the ups and downs of the salience of the three issues is the same with unemployment becoming most salient first, followed by the increasing salience of immigration, which in turn was replaced by the environment.However, there are region-specific variations to this overall pattern with immigration and later the environment reaching a higher peak in north-western Europe.By contrast, when we consider attitudinal change across the same three issues in Figures A1, A2, and A3 in Appendix 2, we see remarkable stability and very little polarisation from the early 2000s to the late 2010s, in line with previous findings.In 14 of 22 European countries, attitudes to immigration became more favourable and only in five did they become more negative, with evidence of greater polarisation only in three countries.There is greater belief that the standard of living of the unemployed is the responsibility of the government in only three countries of the 20 countries considered, with the reverse true in eight countries, with no countries showing greater polarisation.Twelve of twenty countries display greater willingness to sacrifice their income for greater environmental protection, four display no change, and four report less willingness in 2017/18 than in 2008/9, with no evidence of polarisation.
In line with the literature, we see high levels of cross-country volatility for public issue salience and high levels of policy preference stability, making the latter a less plausible predictor of electoral change over time at the national-level.

Figure 3. Determinants of public issue salience section of theoretical framework
We now test whether variation in public issue salience can be explained by changes in societal trends and the party system issue agenda (Figure 3).As shown in Table 1, each of the societal trends described above has a positive, statistically significant effect on the salience of its respective issue when tested alone, in models 1, 4, and 7 respectively.A one standard deviation increase in new immigrants per capita increases the percentage of individuals listing immigration as the most important issue by 8.4 percentage points.A one standard deviation change in the unemployment rate increases the salience of unemployment by 17.3 percentage points.Finally, a one standard deviation change in the temperature anomaly increases the salience of the environment by 0.7 percentage points.When wave controls are added the effect disappears only in the case of temperature anomalies (model 8), possibly the result of greater transnational consistency in climate change or greater public consciousness over time.When the party system issue agenda effects-all of which are statistically significant-are added (models 3, 6, and 9), the effects of the two societal trends remain statistically significant.We also include an interaction term for "days since the previous election" in case the power of agenda-setting wanes over time (see Dekeyser and Freedman 2021), which is statistically significant in the case of unemployment giving party system issue agenda an overall positive effect after two years.Because both the independent variables are standardised, we can compare their relative effects, seeing that societal trends had a far larger effect than party issue salience in the case of immigration and unemployment, while the reverse is true in the case of the environment.The effects of societal trends and public issue salience on the party system issue agenda

Figure 4. Determinants of public issue salience section of theoretical framework
We now test whether variation in the party system issue agenda can be explained by changes in societal trends and public issue salience (Figure 4) using the same method with some key differences.
As shown in Table 2, the effect of public issue salience is positive and statistically significant for immigration and the environment, but not for unemployment.In no case are the societal trends statistically significant, meaning that any effect that they have is via public issue salience.This suggests that, in the cases of immigration and the environment, parties attempt to ride the waves but that they do so in response to public issue salience and only indirectly in response to societal trends.The effects of public issue salience and party system issue agenda on electoral outcomes Next, we turn to considering electoral implications (Figure 5) using the 18 models in Table 3.There are six models each-one for each party family-for each one of the three issues.For the purposes of comparison, both public issue salience and the party system issue agenda are standardised to allow for comparison of effect sizes.For immigration, the public salience is shown to positively affect the vote share of the radical right and negatively affect the vote share of conservative, social democrat and, to a lesser extent, radical left parties (with no statistically significant effect on the liberal or greens).The public salience of unemployment increases the vote share of the radical left and, to a lesser extent, the social democrats, while negatively affecting the radical right and greens (with no statistically significant effect on the conservatives or liberals).Similarly, the public salience of the environment strongly increases the vote share of the greens and reduces the vote share of the radical left and, to a lesser extent, the social democrats (with no statistically significant effect on the conservatives, liberals, or radical right).By contrast, we see that the effect of the party system agenda of each of the three issues on vote share is far more muted for immigration and the environment, where it is significant only, intriguingly, in the case of immigration on green parties and the environment on radical right parties-suggesting that each benefits from increased party competition over these issues.The party system agenda is more important for unemployment, where it enhances the vote shares for the liberals, the radical left, and the radical right, but decreases the vote shares of the conservatives, the social democrats, and the greens.Moreover, the standardised effect sizes show that, for unemployment, the party system issue agenda and public issue salience have similar sized effects for the three "challenger" parties but party system issue salience is far larger for the mainstream parties.We ran several models to further investigate these relationships.At the regional level we found strong negative effects of unemployment on social democrats in southern Europe and strong positive effects in the two other regions.We also ran dynamic Arellano-Bond estimator panel-date models with similar results albeit lower efficiency.

The individual-level effects of salience on vote choice
We now validate the relationship between salience and vote switching at the individual level, using models that include policy preferences to capture spatial proximity voting.As shown in Table 4, using EES data we find individual-level evidence that the public issue salience of, respectively, immigration, unemployment, and the environment increases the chance of switching to radical right, radical left, or green parties respectively.By contrast, conservative and liberal parties repel voters who perceive the environment as highly salient, and the liberals also repel voters who perceive unemployment as such.In these models, only the social democrats are not affected by the voters' salience considerations.We also see that policy attitudes induce switching too.Independent of salience, pro-immigration attitudes induce switching to the social democrats, radical left, and the greens, and preclude switching to the radical right.Opposition to state intervention in the economy encourages switching to conservative parties and precludes switching to social democrat parties.Finally, anti-environmentalism encourages switching to conservative parties and precludes switching to green parties.These results confirm the complementary relevance of spatial and salience voting for electoral change, despite aggregate-level policy preference stability (Druckman and Leeper, 2012).In Table 5, we see the results of fixed effects panel data models using British Election Study data.
Perceiving immigration or the environment as highly salient increases one's chance of intending to vote for the radical right or greens, respectively, while both perceptions reduce one's chance of intending to vote for the conservatives or social democrats.In terms of policy attitudes, we also see effects, highlighting once again the complementary importance of spatial as well as salience voting for electoral change: pro-immigration attitudes encourage switching to both the conservatives and social democrat parties, while reducing the chance of voting for the radical right.Increased anti-environmentalism increases one's chance to switch to the radical right and from the greens, while unemployment attitudes only affect switching to and from both the conservative and social democrat parties.Salience and policy attitude effects on switching to and from the liberal party are not statistically significant, though the directions of effect are theoretically plausible.

Discussion
In this article we built on previous findings and theoretical approaches to offer a novel explanation for the marked, cross-national trends in European electoral results in the 21st century.We take a comprehensive empirical approach, first, overviewing changes in the policy attitudes and public issue salience of three issues-unemployment, immigration, and the environment-across the EU and then using national-level panel data to show that the public salience of these issues is partially rooted in actual unemployment rates, immigration rates and environmental change, to a greater extent than in party agenda-setting.By contrast, the party system issue agenda seems to be driven by the concerns of the public, but not by societal trends.We show that public issue salience of immigration increases the vote share of the radical right and reduces that of conservative, social democrat, and radical left parties; the salience of unemployment increases the vote share of the radical left and social democrats and reduces that of radical right and green parties; while the salience of the environment increases the vote share of the greens and reduces that of the social democrats and radical left.The party system issue agenda's emphasis of immigration and the environment has weaker and only intermittent effects, while its emphasis on unemployment has large and consistent effects for respective party families as we would theoretically expect.We largely validate the effects of public issue salience at the individual-level, incorporating complementary spatial motivations, with cross-sectional pan-European data and panel data from the UK.
In doing so we distinguish between the profound, slow shifts in structural social cleavages and aggregate-level political attitudes, on the one hand, and the short-term volatility of societal events and trends, electoral outcomes, and public issue salience on the other.The basic parameters are changing slowly under the surface whereas what we see in fast-moving party competition is the result of shorter-term considerations that may disappear as quickly as they arise, even though they each are to some extent rooted in real-world changes.This is in line with what Lipset and Rokkan (1967: 94) argued, as well as with the arguments of the key proponents of issue voting and recent findings on agenda-setting.Moreover, party politics is to a large degree a reflection of societal trends and events over which parties have only limited control, as publics are quick to reorient their political priorities according to the perceived urgent matters of the day while maintaining their deeper, more robust convictions.The same can be said of governance: "events, dear boy, events".In short, the world external to politics determines what matters to citizens and, therefore, who wins elections.
Substantially, based on our findings, we can offer two predictions: first, as exogenous trends and events are becoming more transnational, domestic party competition across countries will continue to become subject to trends that are increasingly synchronous, as has happened in Europe; and second, recent changes are potentially fleeting.If the public issue salience and performance evaluations change away from what has benefitted respective non-mainstream parties recently, these parties may lose out again in the electoral competition.Future research should consider testing further societal trends, in the case of our issues including irregular immigration or natural disasters (see McAllister and bin Oslan, 2021).It should theorise why events and trends vary in their effects on an issue's public salience, potentially in terms of perceived risks, novelty, complexity, emotion, etc.Furthermore, our supply-side assumptions highlight the need for future research that should perform similar analyses using the credibility, ownership, and cues of parties on these and other issues (Zaller, 1992;Druckman et al., 2013).

Figure
Figure 1.Theoretical framework

Figure 2 :
Figure 2: The demand-side issue salience of the environment, immigration, and unemployment across the EU28.

Figure 5 .
Figure 5. Determinants of party family vote share section of theoretical framework

Table 1 : Fixed effects panel data models of the effect of societal trends and party system issue agenda on public issue salience
Notes: Standard errors in parentheses.*** p<0.01, ** p<0.05, * p<0.1; dichotomous wave controls not shown James Dennison and Hanspeter Kriesi

Table 2 : Fixed effects panel data models of the effect of societal trends and public issue salience on the party system issue agenda
Notes: Standard errors in parentheses.*** p<0.01, ** p<0.05, * p<0.1;Year controls not shown

Table 4 . Individual-level predictors of intending to switching one's vote to each of the six party families
Notes: Standard errors in parentheses.*** p<0.01, ** p<0.05, * p<0.1;Standard errors clustered by country; Sociodemographic controls not shown.European Election Study, 2014