Political parties abroad as actors of transnational politics

This paper argues that parties abroad are the actors of a new arena for citizenship and party politics. The proliferation of overseas voting and the development of representative institutions for emigrants has transformed and reinforced the civic and political links between sending-states and their diaspora. This has also created new opportunities for political entrepreneurs and political parties tasked with reaching out to citizens living abroad. Yet research on political parties and on transnationalism has almost never crossed paths. This has created a gap in our knowledge on political parties abroad, demonstrating the timeliness of a special issue on political parties abroad. This paper introduces this special issue and presents an overview of the main theoretical questions and debates addressed in the articles. We emphasize existing gaps in the literature and stress the importance of a better understanding of the growing phenomenon of political parties abroad. We also explain why a comparative approach is necessary to tackle the issue of political parties abroad, offering a theoretically-minded framework. Our summaries of the papers in this special issue highlight how they relate to the more general questions discussed in our introduction.


Introduction
In recent decades, globalization and transnationalization processes have raised questions about the civil and political rights of non-nationals on the national territory, and of nationals outside the national territory (Anderson, 1992;Arrighi & Bauböck, 2017;Meseguer & Burgess, 2014;Safran, 1997;Sayad, 1999). On this last aspect, emigrants 1 have increasingly been granted civil and political rights in their country of origin: not only voting rights, but also representation in specific institutions or sometimes even in national parliaments (Ellis et al., 2007;Gamlen, 2019;Koinova & Tsourapas, 2018;Pedroza, 2019;Rhodes & Harutyunyan, 2010). Between 1989 and 2020, the number of countries granting voting rights to non-resident citizens increased from 31 to 151. More than half of them implemented such reforms after 2000. 2 Today, almost all democracies offer some form of distant voting. Since the beginning of the twenty-first century, 16 countries (including five Member States of the European Union) have even granted their emigrants the right to directly elect members of parliament in one or more constituencies located outside the territorial boundaries of the state (Burgess & Tyburski, 2020;Collyer, 2014b;Palop-García, 2018). These transformations concern millions of citizens: in 2019, an estimated 3.5% of the world population lived outside their country of birth (United Nations, 2019).
These reforms have important political and electoral consequences. Emigrant voters can influence the outcome of elections, as in the case of Romania in 2009 (Burean, 2011) or Italy in 2006 (Laguerre, 2013). The magnitude of these reforms has created a new arena for electoral politics, and for parties abroad as central actors of extraterritorial elections. This extension of the democratic sphere of established nation states and its political and electoral consequences constitute opportunities and challenges for political parties. They face the choice of engaging or not in this new arena. Looking into these important developments, the Special issue analyses whether, why and how political parties develop in this new arena abroad.

Parties as actors of transnational politics: the missing link
Given their significance, these reforms have been at the heart of a growing literature since the 1990s (Collyer, 2013;Lafleur, 2013a;Laguerre, 2013). There has been a progressive recognition that 'citizens living abroad are not a random subsample of the home-based population and thus deserve special attention' (Goldberg & Lanz, 2019, p. 18). However, the literature is currently split between scholars who focus on different dimensions of emigration and diaspora, and others who focus on multi-level (party) politics. While the first often address emigration from an individual-level perspective and focus on emigrants' social and political rights, they tend to ignore the partisan dimension of emigration. The second field, that of electoral studies and multi-level (party) politics, tends to ignore the extraterritorial dimension of electoral and party politics. The purpose of this Special issue is to connect these literatures and to put parties abroad at the centre of the focus.

Transnationalism studies and the political engagement of emigrants
The concept of transnationalism has been brought into common academic usage in the 1990s by Linda Basch, Nina Glick Schiller, and Cristina Szanton Blanc, who refer to transnationalism as 'the processes by which immigrants forge and sustain multistranded social relations that link together their societies of origin and settlement' (Basch, 1994, p. 7; see also Glick Schiller et al. 1992). Alejandro Portes and his colleagues add that the transnational field is 'comprised of a growing number of persons who live dual lives: speaking two languages, having homes in two countries and making a living through continuous regular contact across national borders' (Portes et al., 1999, p. 217). Steven Vertovec provides a broader and more flexible definition where transnationalism refers to the 'multiple ties or interactions linking people or institutions across the borders of nation-states' (Vertovec, 1999, p. 447).
Since then, transnationalism has developed into a very dynamic research field linked to migration studies. This literature stresses how nation-states are progressively structured and 'territorialized' in their relations with emigrants (Boccagni, 2014;Gamlen, 2019). In return, it shows how recent reforms enable emigrants to be politically active citizens, both in their host country and in their country of origin (Bauböck, 2003;Collyer, 2013;Guarnizo et al., 2003;Pedroza, 2019). There is thus a double dynamic at play, where emigration is constructed as a political space from above by the nationstates, and from below by emigrants who co-construct and engage (or not) in this new political space, thereby contributing to the transformation of the nation-states (Burgess, 2020). In that view, transnationalism is a continuum where emigrants engage in multiple modes of participation that are more or less intensive (Lafleur, 2013a;Waldinger, 2013), and that can be oriented towards the country of origin (and thus have a transnational orientation), towards the country of residence (and therefore have an assimilationist orientation) or even towards other migrants (and thus be decentralized and have a diasporic orientation) (Landolt, 2008, p. 54). By emphasizing these dynamics, this literature questions the previous assimilationist perspective according to which emigrants gradually integrated into their host country and progressively cut ties with their country of origin. Researchers emphasize that emigrants are not rootless individuals enrolled in a process of integration into their host country, but are citizens divided between a homeland and a host country, able to invest or project socially, politically and cognitively in two countries, creating a transnational space in the process (Portes et al., 1999;Waldinger, 2013). Research has shown how host countries' migration policies affect the political activity, organisation, and lobbying capacities of emigrants, but also how emigrants can act as lobbying agents to influence politics in the home country (Burgess, 2020;Naujoks, 2017). At the same time, governments increasingly use emigrants on their territory to act as foreign policy agents (Marinova, 2017) and emigrant associations play an important role in host countries (Blanch, 2005;Escobar, 2010;Morales & Jorba, 2010). These studies have in common that they stress how the dynamics work both from the bottom-up and from the top-down and emphasize divided loyalties that are inherent among emigrants.
This 'transnational turn' in migration studies started in the 1990s and has become mainstream in the last decade (Bauböck & Faist, 2010;Dufoix et al. 2010;Lafleur, 2013a;Maas, 2013). It has pushed the research on the political involvement of emigrants into several directions. The first one analyses 'diaspora politics' (Østergaard-Nielsen, 2003) and focuses on the 'hot' activism of diasporas and exiled minorities in conflict with a state of origin (Fair, 2005;Pedraza, 2007). These studies look into how organized minorities continue abroad a political struggle that is rooted at home (Cochrane, 2015).
Another trend of research analyses 'emigrant politics' (Østergaard-Nielsen, 2003) and focuses on the political activities of economic migrants from countries of emigration to countries of immigration (Argun, 2017;Délano, 2011). These studies investigate migrants' reactions to their marginalization or the terms of their integration in the host country. They emphasize the crucial political role of economic, social, and political remittances, i.e. transfers of goods, projects, but also norms and ideas, from the host country back to the country of origin (Boccagni & Ramírez, 2013;Collyer, 2013;Lacroix et al. 2016).
More recently, the literature has investigated the drivers of political engagement of emigrants in their host or home countries (Ahmadov & Sasse, 2016;Burgess, 2014;Ciornei & Østergaard-Nielsen, 2020;Collyer, 2014b;Goldberg & Lanz, 2019;Lafleur, 2013a). Following the classic theories on political participation (van Haute, 2009), these studies have looked at micro-level and macro-level drivers of participation. At the individual level, they have looked at the role of resources and motivations to explain the political engagement of emigrants. When it comes to resources, studies have mainly focused on classic socio-demographic characteristics such as age or gender (Burgess, 2014;Guarnizo et al., 2003;Jones-Correa, 1998), education, occupation or socioeconomic status (Guarnizo et al., 2003;Jaulin, 2016), but studies have also looked into the degree of integration into the host society (Ahmadov & Sasse, 2016;Jones-Correa, 1998;Leal et al. 2012), and networks and social connections with the country of origin (Ahmadov & Sasse, 2016;Burgess, 2012;Careja & Emmenegger, 2012;Ciornei & Østergaard-Nielsen, 2020).
When it comes to motivations, research has pointed the paradox of political engagement of emigrants: while the costs of engagement are high, the benefits are low, and participation therefore does not seem rational (Waldinger, 2013). Indeed, the state of origin has a limited capacity to act in favour of the emigrants in their host country (Fitzgerald, 2009). Furthermore, the benefits or incentives for activism are seemingly low. Research suggests that active emigrants are motivated by selective symbolic incentives where participation is a way to preserve their self-esteem in a context of loss of status after migration (Glick Schiller, 2005;Skrbiš, 2017). However, this contradicts studies that focus on resources, which emphasized that active emigrants are characterized by higher levels of education, high social capital and stability of status in the host country (Guarnizo et al., 2003).
At the macro-level, studies have investigated the role of political opportunity structures in the host country (Ahmadov & Sasse, 2016;Ciornei & Østergaard-Nielsen, 2020;Escobar et al. 2015;Lafleur & Sánchez-Domínguez, 2015) or in the country of origin (Bauböck, 2010;Burgess, 2014). However, the effects of these factors are debated. For example, some studies argue that migrants who obtained citizenship in their host country are less likely to engage in homeland politics (Waldinger & Duquette-Rury, 2016), and that migrants who keep the citizenship of their home country are more likely to do so (Leblang, 2017). But other studies do not find any effect of naturalization and dual citizenship on transnational political engagement (Guarnizo et al., 2003;Schlenker et al. 2017). Ahmadov and Sasse (2016) explain these contrasted findings by a differentiated effect depending on the type of participation. They show that Ukrainian emigrants 'who have citizenship or permanent residence in the host country are likely to be considerably less engaged in community political activities, but not in electoral activities' (Ahmadov & Sasse, 2016, p. 101).
Overall, the literature on transnationalism lays solid foundations to understand and explain citizenship and political engagement of emigrants. However, it mainly focuses on macro-level features (legal framework, waves of migration, opportunity structures) and individual-level determinants (resources, incentives and motivations). In doing so, it largely overlooks meso-level aspects, especially how operators such as candidates, activists, and political parties, adapt to the new transnational context. This Special issue intends to fill this gap by connecting the literature on transnationalism to the literature on party politics.

Multi-level parties and electoral politics
Electoral studies have investigated the voting behaviour of migrants in their host country (Bird et al. 2010) but also increasingly in their home country. The issue of distant voting by emigrants is now covered by a wide range of research (Barabantseva & Sutherland, 2011;Barry, 2006;Bauböck, 2017;Brand, 2006;Caramani & Grotz, 2015;Ciornei & Østergaard-Nielsen, 2020;Rhodes & Harutyunyan, 2010). Some studies analyse the diffusion of distant voting and the role of norm diffusion and party strategies in the process (Turcu & Urbatsch, 2014. Others look into the normative implications of these developments (Bauböck, 2007;López-Guerra, 2005;Spiro, 2006). But the largest and fastest growing part of the literature adopts a more analytical perspective. The main goal is to explain voter registration, turnout, or electoral choices among emigrants (Bhatti & Hansen, 2016;Burgess & Tyburski, 2020;Collyer, 2014a;Hartmann, 2015;Lafleur, 2013a). These studies engage in the dilemma that emigrants face regarding the political space to engage in and stress three main drivers of participation in distant voting (Chaudary, 2018;Finn, 2020;Goldberg & Lanz, 2019). First, electoral participation can be an expression of belonging and symbolic attachment to the nation more than a sign of deep political involvement in the country of origin (Boccagni, 2011;Itzigsohn, 2012;Knott, 2017). In that view, it would be less about influencing the outcome of an election than about expressing one's loyalty to the state of origin. Second, emigrant voters may also want to express their own specific interests (Bauböck, 2009), especially when the emigrant vote is visible, counted separately, and even more so when it contributes to directly elect specific representatives (Collyer, 2014b). Third, emigrants may be driven by the will to steer one's country of origin politically, either because of longterm political convictions or because living abroad changed their perspective on their home-country (Klekowski von Koppenfels, 2014). Overall, this literature primarily focuses on emigrants' electoral behaviour. If some studies also shed light on the role of parties as mobilizing agencies in the electoral process (Burgess, 2018(Burgess, , 2020Østergaard-Nielsen & Ciornei, 2019;Paarlberg, 2019;Wellman, 2015), parties as organizations are not the central focus.
The field of party politics offers numerous classic typologies and theories on party development, organization, and functions. However, they have mostly been developed in the context of nation-states, which reflects a form of dominant methodological nationalism (Amelina et al. 2012;Schakel & Jeffrey, 2013;Wimmer & Glick Schiller, 2002). Yet the processes of decentralization and continental integration have pushed the field to a turning point. Researches recently started to focus on political parties in multilevel contexts (Detterbeck, 2012;Detterbeck & Hepburn, 2010;Golder et al. 2017;Gómez-Reino, 2018;Swenden & Maddens, 2009). This shift of perspective highlighted the ability of parties to invest in the new opportunities offered by decentralization and European integration. Yet this new perspective still tends to ignore the extra-territorial dimension of party politics. Our knowledge on the origins, development, organization, and role of political parties abroad is still sparce. It is often restricted to case studies and focuses heavily on the electoral dimension and the mobilizing role of parties, with some recent exceptions (Kernalegenn & van Haute, 2020;Rashkova & van der Staak, 2020a, 2020b. By bringing two important fields of the literature together, our proposed Special issue fills a clear gap. Using the 'mother' parties at home and the classic theories of party organisations (Katz & Crotty, 2006;Scarrow et al., 2017), but also Europarties and their relation to national parties (Bardi et al., 2014;Day & Shaw, 2003Gagatek, 2009;Gagatek & Van Hecke, 2014;Lightfoot, 2006) as reference points, the main goal of this Special issue is to investigate, in a comparative perspective, (1) what parties abroad are, (2) when and why do they emerge and develop, (3) how they organize, and (4) what roles do they play.
What are parties abroad? Case selection strategy Parties abroad can be differentiated based on their more or less conflictual relation to the home country. In the case of diaspora politics (as conceptualized in Østergaard-Nielsen, 2003), parties abroad can be related to the 'hot' activism of diasporas and exiled minorities in conflict with the home country. In that case, parties are the continuation abroad of a political struggle that is rooted at home, most often in authoritarian or dictatorial regimes but not always. In the case of emigrant politics (as conceptualized in Østergaard-Nielsen, 2003) and external citizenship more generally, parties abroad are related to a peaceful participation in the politics of their home country.
Parties abroad can also be differentiated according to the location of their headquarters: either they are extensions of political parties in the home country or they are new political movements organized abroad. Therefore, they can be a branch of a mother party in the home country or provide a distinct political offer to emigrants.
These two criteria lead to a classification of political parties abroad in four party types (Table 1). Emigrant party branches, such as Labour International, are based on emigrant politics with headquarters in the home country. They are extraterritorial branches of the mother party. Diaspora or anti-diaspora parties, such as the Rassemblement Constitutionnel Démocratique (Democratic Constitutional Rally, RCD) in Tunisia or the Turkish Justice and Development Party (AKP), are based on diaspora politics with headquarters in the home country. Their main aim is to organise the diaspora either in favour or against the home state and its regime. Emigrant parties, such as the Alliance Solidaire des Français de l'Étranger or the Movimento Associativo Italiani all'Estero, are parties based on emigrant politics with headquarters abroad. They focus on emigrant politics and mobilize members with an emigrant background. Finally, forbidden parties, such as the National Democratic Party of Tibet, rely on diaspora politics with headquarters abroad ( van Haute & Kernalegenn, 2020). They mostly operate in contexts of dictatorship when a normal party life is impossible in the home country and therefore continues abroad with most often the aim to overthrow the regime at home or to create a secessionist state.
This Special issue focusses on emigrant party branches, that is, parties that have roots in emigrant politics and have developed some forms of organization and activities abroad. The selected cases vary in terms of type of regime (based on the Freedom House Index), institutional setting and rights granted to emigrants (from no external political rights to voting rights, to specific, direct representation). While Avital Friedman and Ofer Kenig analyse the case of Israeli parties (free country, without external political rights), Nicolas Fliess investigates the cases of Bolivian and Ecuadorian parties in Barcelona (partly free countries, Bolivia grants external voting rights to their citizens, while Ecuador has also granted emigrants special seats in the national parliament). Mari-Liis Jakobson, Tõnis Saarts, and Leif Kalev investigate the case of the Conservative People's Party of Estonia (Eesti Konservatiivne Rahvaerakond -EKRE) that has developed branches in Finland under external voting rights in Estonia. In their paper focusing on membership of parties abroad, Sue Collard and Tudi Kernalegenn look at the three main British parties, the Conservatives, Labour, and the Liberal Democrats, all three parties operating under the same setting of external voting rights. Finally, Felix von Nostitz analyses the transnational branches of the two mainstream parties in France (with direct representation), Germany, and the United Kingdom (with external voting rights but no specific, direct representation), allowing for contrasting cases.
While some of the papers are case studies and other are comparative, the overall orientation of the Special issue is comparative. The case selection strategy, covering the range of parties abroad in various institutional settings (types of regimes and electoral rules), allows us to offer in this introduction a synthetic framework for the analysis of political parties abroad. All papers use original data to address the questions of the emergence, development, organization, and functions of parties abroad. In doing so, they contribute to a better understanding of transnationalism, long-distance democracy, and party politics.

When and why do parties abroad emerge and develop?
The papers of the Special issue pay a specific attention to how party branches emerge abroad: Are parties abroad submitted to the same regulations as parties at home? How does it affect their development? What are the incentives and barriers for parties to emerge and operate abroad?
As the classic literature on parties points, the development of party organizations in parliamentary democracies was not an obvious path. Several normative and pragmatic barriers to their development existed (van Haute & Sauger, 2018). These barriers were progressively lifted while incentives to create parties increased, especially with the expansion of suffrage (Sartori, 2011(Sartori, [1976, p. 23) and parliamentarization (Scarrow, 2006).
The same is true for parties abroad, who face opportunities and constrains in their development. Emigrants sometimes have weak to no link with their home country and therefore weak interest for home politics. Home politics has little impact on their dayto-day life in their host country and their participation rate is usually lower than at home, sometimes almost negligible (Ciornei & Østergaard-Nielsen, 2020). Furthermore, the cost of investing abroad can be high for parties, especially if emigrants are scattered in a large number of countries or localities with a weak population density, as shown by von Nostitz (2021) in this Special issue. Besides, the opinions and political preferences of emigrants are hard to picture since they are not surveyed by opinion polls. Yet despite these barriers, parties engage in the development of activities and branches abroad. There must be alternative incentives for parties to do it.
The specificity of parties abroad is that these incentives are the result of the contexts both in the home and host countries (Zederman, 2020). The legal and institutional frameworks in the host country can constitute a barrier to the development of parties abroad. Not all host countries authorize and recognize foreign political groups, and they do not necessarily allow all political groups to flourish (Lafleur, 2013a). The legal and institutional frameworks in the home country constitute another strong opportunity or constrain for the development of parties abroad ( van Haute & Kernalegenn, 2020). More specifically, four dimensions matter: voting rights, electoral rules, representation, and campaign rules. In this Special issue, von Nostitz (2021) shows how the legal framework creates higher incentives for the development of parties abroad in France, where emigrants have voting and special direct representation rights, compared to Germany and the U.K.
However, parties often go around legal and institutional barriers. Furthermore, favourable institutions do not always precede the development of parties, as shown by Duverger (1951) who pointed that some parties emerged within a social movement, to represent a specific group, or around a salient issue. The same applies to parties abroad, whose emergence can be tied to the sociology of migrations and the representation of specific interests of emigrants (Burgess, 2018;Lafleur, 2013b; van Haute & Kernalegenn, 2020). First and foremost, being able to identify a clear ethnos rather than demos can act as the main organizing political principle of parties abroad. For instance, Friedman and Kenig (2021) show in this Special issue how Israeli parties develop activities abroad to maintain relations with the large Jewish diaspora. Citizenship and voting rights do not play a role here; rather, it is the identification of a common ethnos that serve as incentive. Several factors can facilitate the identification of an ethnos among emigrants, as shown by Jakobson et al. (2021) in this Special issue: their concentration in communities or homogeneous neighbourhoods in cities, the existence of national media to maintain a link and inform emigrants abroad on national politics; the existence of separate schools that can act as socializing institutions and contribute to community building.
Finally, political actors also matter. First, a positive evaluation of the costs and benefits of developing a party (branch) abroad is often regarded as a prerequisite to establishing a party abroad (Aldrich, 1995;Kalyvas, 1996). Furthermore, in democratic regimes, the process of setting up a party (branch) abroad tends to be bottom-up and relies on emigrants organized in communities ( van Haute & Kernalegenn, 2020). These communities are not always overtly political but can nevertheless be associated with a party and later develop into informal political organizations, and then into more formal party branches. As shown by Collard and Kernalegenn (2021), local entrepreneurs or former activists are instrumental in the development of parties abroad. This bottom-up process also means that the mother party at home has often little control over the process, at least at the beginning. Yet quite rapidly, party branches institutionalize and the mother party takes back control of the structures and activities developed abroad, as shown by Jakobson et al., (2021) in this Special issue.

How do parties abroad organize?
The papers of the Special issue also tackle the question of the organisational structure of parties abroad: Which organisational structure do they adopt (Katz & Mair, 1995;Krouwel, 2006)? How does the connection with the mother party operate? What are their organisational specificities? Parties at home have been characterised as increasingly professionalised and relying on capital-intensive resources obtained from the state, and less on free labour from their declining membership basis (Poguntke et al., 2016). How much do parties abroad look like their mother party on these dimensions?
When they institutionalize, the most common choice for party branches abroad is to replicate the organizational structure of the mother party ( van Haute & Kernalegenn, 2020). Parties amend their statutes to allow emigrants to be regular party members and increasingly grant them the same rights as members at home in the internal decisionmaking processes. Mother parties set up formal internal procedures to recognize branches abroad (see Jakobson et al., 2021). Branches abroad then share the same organizational characteristics as branches in the home country in terms of composition of the main bodies and in terms of daily functioning of the branch (see von Nostitz, 2021). Party branches abroad are often grouped into a federation of party branches abroad. This means that they enjoy representation in party bodies and that their delegates or representatives can take part in annual meetings or party conferences, very much as other federations of party branches at home. A position of manager of party branches abroad is sometimes created (Kernalegenn & Pellen, 2020). However, using the example of British parties, Collard and Kernalegenn (2021) show that weakly institutionalized parties at home will develop weakly structured branches abroad.
The progressive institutionalization of parties abroad and the increased control of the party-in-central-office over these branches does not happen without tensions (see Jakobson et al., 2021). These tensions are classic in new parties passing thresholds in their lifecycle (Pedersen, 1982) and tend to appear at crucial moments in the party's life, such as the first candidate selection process for elections. As shown by Jakobson et al. (2021), these tensions can be exacerbated in the case of parties abroad due to the geographical and political distance with the centre, specific challenges due to the hostility of cultural associations of emigrants towards the party, the composition of the emigrant community, or the high turnover in members and volunteers in the host country, as emigrant life is characterized by more mobility than at home (see also Kernalegenn & Pellen, 2020).
But the institutionalization and the increased control from the party-in-central-office is not always seen as an intrusion from parties abroad, who can welcome the support from the mother party.

What role do parties abroad play?
Last, the papers of the Special issue offer a better understanding of the role and functions of political parties abroad.
At home, parties constitute a means to render intelligible a series of processes for citizens. They are often regarded as indispensable to the functioning of political representation and democracy. The literature has identified three main categories of functions (Key, 1964;Wright, 1971;Sartori, 2011Sartori, [1976; Panebianco, 1988Panebianco, [1982; Lawson & Merkl, 2014): (1) functions exercised in relation to the electorate, (2) as an organization, or (3) in the context of governmental participation ( van Haute & Sauger, 2018). Mother parties have been described as having shifted towards more governmental functions to the detriment of linkage functions. However, the inclusion of emigrants in the process of representation is still often under-developed and parties abroad are only very indirectly exercising governmental functions. How does this specificity affect the role and functions developed by parties abroad?
Papers in this Special issue show that parties abroad are skewed towards the participation side of the linkage function. Especially when they have bottom-up origins, parties abroad engage in socio-cultural activities in order to build a network of activists abroad, often in connection with pre-existing associations or groups (see Fliess, 2021;Jakobson et al., 2021;and Collard & Kernalegenn, 2021 in this Special issue). They provide help and services to emigrants, and organize sport, cultural or social activities (Klekowski von Koppenfels, 2014;Lillo, 2019). These activities are illustrative of their transnational character: they are geared towards emigrants in the host country but at the same time cultivate a sense of community among emigrants from a common home country. Thereby, parties abroad create linkages with emigrants, socialize and integrate them into the political system, but also generate identification and loyalty towards the home and host countries.
Parties abroad are often subordinated to pre-established associations or groups. As shown by Friedman and Kenig (2021), Israeli parties develop links with the World Zionist Organisation or youth movement. They benefit from representation in these organizations, gain access to financial resources, policy formulation, or even electoral influence. In the absence of voting rights, parties create a link with the communities they want to relate to abroad. Similarly, Fliess (2021) shows how parties link with migrant associations through infiltration, co-optation, and cooperation to mobilize for campaign purposes. In that sense, parties' mobilization cycles aren't necessarily determined by 'local life' but are very dependent on the cycle of party politics back home. Election years become their busiest years while non-election years focus on political discussion and awareness-raising.
However, with their institutionalization, parties abroad also progressively develop usual branch activities. All parties face difficulties in maintaining activism and political engagement of their grassroots (van Haute & Gauja, 2015). The case studies in this Special issue reveal that parties abroad face specific barriers and incentives to mobilize emigrants. They face a higher dispersion of their grassroots on the territory of the host country, which makes the organization of regular party activities more complex. Online tools are increasingly used to compensate for this difficulty (Jakobson et al., 2021). At the individual level, reactive transnationalism against policies from the national government can act as powerful mobilizers (Collard & Kernalegenn, 2021). A high level of pre-existing partisanship of emigrants in the home country constitutes another facilitating factor. This partisanship does not necessarily have to be developed towards the actual parties abroad. But parties abroad are subject to the same incentives to partisan participation as mother parties (Whiteley & Seyd, 1996).
If the institutional framework allows it, parties abroad also engage in the representation side of the linkage function. As shown by Fliess (2021) or Collard and Kernalegenn (2021) in this Special issue, they engage in online and offline campaign activities and encourage the registration of overseas voters during the election period. They rely on influencers, leaders in the community and vote multipliers, encourage direct contact with voters, organize campaign events and meetings for specific candidates, fundraising events, etc. When parties abroad are more institutionalized, they can rely on the help of the mother party for campaign material (Jakobson et al., 2021). The distance with the mother party provides autonomy and flexibility in their choices of campaign strategies and themes. Emigrants are viewed as a special electorate and the choice of campaign strategies are linked to the historical sociological composition of the diaspora. Strategies are also related to the capacity of the party abroad to penetrate and mobilize the emigrants' groups and organizations, as shown in the case of EKRE (Jakobson et al., 2021).
Next, parties abroad also simplify and structure electoral choices. They are torn between acting as advocates of the party's current programme and representation of local interests (Klekowski von Koppenfels, 2014). As local representatives of emigrants, they aggregate the interests of emigrants, provide policy positions and services. They develop specific policies for emigrants and lobby home governments to voice the interests of emigrants, as has been the case concerning the consequences of Brexit for British living in European countries (Collard & Kernalegenn, 2021). Parties abroad may also act as champions of emigrants towards the host country. They sometimes strive (generally indirectly, notably via migrant associations or sister parties) to integrate the emigrant issue into the agenda of local social and political actors. Finally, parties abroad also lobby the mother party at home to integrate topics that are important to their constituents. In sum, parties abroad act towards three principals: the home country, the mother party, and the host country ( van Haute & Kernalegenn, 2020). This can complicate their action on the ground.
Parties abroad also act as the ambassador of the mother party and promote its values and ideology (see Jakobson et al., 2021). They network with other parties that share a similar ideology, which allows them to benefit from material and symbolic resources. However, this transnational cooperation can be made difficult if the ally party in the host country sits in government when the party abroad sits in the opposition (the former seeking for more ideological moderation than the latter) or in case of ideological discrepancies. In this context, parties in the home and host countries will seek for cooperation on a cultural level rather than on a political level.
Finally, parties abroad also engage in informal activities aimed to foster ties with international elites and lobbies. For instance, they may engage in fund-raising among business (even if legally limited), especially for intra-party contests such as candidate and leadership elections that are not as strictly regulated as general elections. This funding dimension is quite important for British parties abroad, for instance (Collard & Kernalegenn, 2021).
Ultimately thus, parties abroad tend to develop activities and roles that are much more focussed on the party on the ground than parties at home. In relation to the electorate, parties abroad perform the classic functions of parties: they simplify and structure electoral choices, serve as channels of communication, educate citizens, participate in their socialization and their integration into the political system, generate symbols of identification and loyalty both at home and in the host country. They also channel political participation. However, their functions as organizations are much less developed. Except in contexts where emigrants are granted specific representation, parties abroad do not engage much in the recruitment and selection of political staff. They may do it indirectly, via informal fund-raising activities. They do however perform a programmatic function, which has the specificity of being oriented towards three principals: the mother party, the host country, and the home country. Finally, and contrary to mother parties at home, the government function of parties abroad is atrophied. These discrepancies between the roles of parties at home and abroad is a gap that the geographical distance does not help to fill. This might constitute one of the major challenges for the development of parties abroad.

Political parties abroad as actors of transnational politics
Political parties abroad are not a new phenomenon. Their existence is as old as that of political parties. However, in contrast with parties at home, they are in a process of quick development. The main reason for this is the development of distant voting. This has created a new arena for party politics.
However, political parties abroad are not limited to democratic countries generous with their emigrants. It is now a quasi-universal phenomenon. There are many forms of parties abroad, as many as there are functions for parties abroad: from political socialization to get-out-the-vote efforts, to representation of emigrants. Despite important constraints, such as distance, political parties abroad have been able to carry out most of the functions of parties at home.
However, political parties abroad have an atrophied governmental role. Until now, political careers abroad are still rare, except in a small number of countries that have implemented parliamentary representation for emigrants. If this new trend continues, political parties abroad will certainly continue to develop. And in doing so, they reinvent the territoriality of democracy and of citizenship.

Acknowledgements
This Special Issue is the outcome of an international conference organised by the ISPOLE (UCLouvain) and the Cevipol (Université libre de Bruxelles). We thank all participants at the conference for the fruitful discussions and comments on the papers.

Authors' contributions
This introduction was co-written by the two mentioned authors. All authors read and approved the final manuscript.

Authors' information
Emilie VAN HAUTE is Chair of the Department of Political Science at the Université libre de Bruxelles (ULB) and researcher at the Centre d'étude de la vie politique (Cevipol). Her research interests focus on party membership, intra-party dynamics, elections, and voting behaviour. Her research has appeared in West European Politics, Party Politics, Electoral Studies, Political Studies, or European Political Science. She is co-editor of Acta Politica. Tudi KERNALEGENN is a research fellow at the Centre de recherche sur l'action politique (CRAPUL), Université de Lausanne (UNIL), and a fellow at the French IC-Migration. His research focusses on territorial politics, with an emphasis notably on regional politics, politically committed emigrants and political parties. He has edited many books on political parties, on regional politics and on migrations, published notably by Routledge, Presses Universitaires de Rennes, Berger-Levrault and Ottawa University Press. His research also appeared in Regional and Federal Studies, Journal of Political Ideologies, or Revue internationale de politique comparée.

Funding
This Special issue is the outcome of a conference that benefited from the support of the Association belge francophone de science politique (ABSP), the Fonds national de la recherche scientifique (FNRS), the Institut de sciences politique de l'UCLouvain (ISPOLE), the Centre d'étude de la vie politique de l'Université libre de Bruxelles (Cevipol) and the Agence universitaire de la francophonie (AUF). For this project, Tudi Kernalegenn has also received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant Agreement No. 705872. The Special issue itself benefitted from the financial support of the French Collaborative Institute on Migration, coordinated by the CNRS under the reference ANR-17-CONV-0001.

Availability of data and materials
Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.

Competing interests
The authors declare that they have no competing interests.