The ‘transnational turn’ in migration studies, beginning in the early 1990s, has been the subject of vigorous debate by migration scholars, with ‘transnationalism’ (and its family members – transnational, transmigrant, transnationality) becoming contested terms as theorists discuss and develop different strands of the literature. The transnational paradigm has been enthusiastically accepted by those, from various disciplines, searching for a conceptual framework within which to situate empirical findings illustrating multiple and intense cross-border economic connections between migrants and their countries of origin (partly in response to dissatisfaction with older, already established models of migration scholarship). A number of thematic fields have been developed within the literature including transnational economic ties (Portes 1996; Guarnizo 2003; Sana 2005; Djelić & Quack 2010), political (Ostergaard-Nielsen 2002; Bauböck 2003; Guarnizo, Portes & Haller 2003; Bordes-Benayoun 2010; Lafleur 2013; Nye & Keohane 1972), cultural (Appadurai 1996; Hannerz 1996; Kennedy & Roudometof 2002; Jackson, Crang & Dwyer 2004; Koundoura 2012) or social (Faist 2000; Pries 2001; Vertovec 2003; Levitt & Glick Schiller 2004; Dahinden 2005; Bradatan, Melton & Popan 2010). Within the more general field on transnationalism, more specialist and focused ‘sub-fields’ of study have also grown and developed, for example on gender, transnational families and parenting (Pessar & Mahler 2003; Salih 2003; Skrbiš 2008; Carling, Menjivar & Schmalzbauer 2012; Baldassar & Merla 2013; Oso & Ribas-Mateos 2013), ‘community’ transnational practices (Guarnizo & Smith 1998; Riccio 2001; Batahla & Carling 2008; Bruneau 2010; Halilovich 2011b) and ‘sub-sets’ of the main themes, for example citizenship within transnational political literature (Kivisto 2001). However, the concept has also been interrogated by those who call into question how the acts and behaviour of ‘transnationals’ differ from the practices of international migrants through the ages.

Development of the field
Introduced into academic literature in the context of international relations in the 1970s by the work of Joseph Nye and Robert Keohane (1972), the concept of transnationalism is widely accepted to have been brought into common academic usage in the 1990s by American sociologists Linda Basch, Nina Glick Schiller and Cristina Szanton Blanc (1994; and Glick Schiller, Basch & Szanton Blanc 1992, 1995) and later developed by Alejandro Portes and his colleagues (inter alia 1996, 1999, 2001). Peter Kivisto (2001) in his review of the different ways that transnationalism has been conceptualised by migration scholars identifies a third ‘version’ of transnationalism in the publications of political scientist Thomas Faist (see especially Baubock & Faist 2010 and Faist, Fauser & Reisenauer 2013) who Kivisto attributes as developing the ‘most rigorously systematic articulation of the term’ (Kivisto 2001, 551). Observers (Schunck 2014) have, however, highlighted earlier work that could be considered to document transnational migratory practices: Zlatko Skrbiš (2008, 232) reviews William Thomas and Florian Znaniecki’s The Polish Peasant in Europe and America (1918) as ‘the first systematic study of transnational family life ever conducted’.

In their Nations unbound Basch, Glick Schiller and Szanton Blanc (1994, 7) outlined a definition of transnationalism and those who participate in the process as ‘transmigrants’:

We define ‘transnationalism’ as the processes by which immigrants forge and sustain multi-stranded social relations that link together their societies of origin and settlement. We call these processes transnationalism to emphasise that many immigrants today build social fields that cross geographic, cultural, and political borders. Immigrants who develop and maintain multiple relationships – familial, economic, social, organisational, religious and political – that span borders we call ‘transmigrants’. An essential element of transnationalism is the multiplicity of involvements that transmigrants sustain in both home and host societies.

In reviewing earlier studies on transnationalism, some scholars have lamented the lack of a commonly-agreed theoretical framework in which to site empirical work; indeed the beginning of every discussion is typically dominated by highlighting the challenges of researching transnational practice in the absence of an agreed definition of scope (Al-Ali & Koser 2002). Portes, one of the most frequently cited scholars of transnationalism, writing in 1999, stated that the emergent transnational social field ‘lacks both a well-defined theoretical framework and analytical rigour’ (Portes, Guarnizo & Landolt 1999, 218). Thomas Faist, Margit Fauser and Eveline Reisenauer (2013, 9), writing fourteen years later, state ‘transnational approaches certainly do not (yet) form a coherent theory or set of theories’. Rejecting the term ‘transmigrant’ as employed by Basch, Glick Schiller and Szanton Blanc as being extraneous to the ‘earlier and more familiar’ term of ‘immigrant’ (Portes, Guarnizo & Landolt 1999, 219), Portes and colleagues maintain 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’ (ibid, 217).

In their attempts to ‘turn the concept of transnationalism into a clearly defined and measurable object of research’ (ibid, 218), Portes and his colleagues have delineated relatively prescriptive conditions under which a migrant could be considered to be operating in a transnational sphere. In particular it is the sustained and regular contact across borders over time which, Portes insists, is a prerequisite for any activity to be considered transnational in nature. Occasional or ‘one-off’ payments to friends or family in the country of origin or irregular visits would not be considered to be of a level deemed intense enough to warrant the transnational label being applied. This focus is clearly couched within empirical studies of the experiences of labour migrants, as has been pointed out by others (Al-Ali, Black & Koser 2001) and is not so easily translated into the lived experiences of those migrating with different motivations, especially forced migrants. Indeed, Portes himself acknowledges that in applying such restrictive criteria to the concept, ‘very few’ migrants could be considered to be engaging in what could be termed as ‘transnationalism’. Others have however advocated for a less restrictive application of the concept (Jackson, Crang & Dwyer 2004; Al-Ali, Black & Koser 2001).

A broader definition of transnationalism is provided by Steven Vertovec (1999, 447) as referring to ‘multiple ties or interactions linking people or institutions across the borders of nation-states’. Vertovec (1999) identified six interconnected themes in which the phenomenon of transnationalism is evidenced: as a social morphology, as a type of consciousness, as a mode of cultural reproduction, as an avenue of capital, as a site of political engagement, and as a reconstruction of ‘place’ or locality. Vertovec circumvents the debate around what is ‘new’ about transnationalism by stating: ‘Transnationalism (as long-distance networks) certainly preceded “the nation”’ (Vertovec 1999, 447).

An essential element of the conceptualisation of the transnational paradigm is the argument that those who could be considered to be transnational actors are leading ‘dual lives’ and the ways in which transnational actors are ‘both here and there’ or ‘neither here nor there’ seems to be a fundamental difference in the ways that different scholars approach the process. Glick Schiller and her colleagues (Glick Schiller, Basch & Szanton Blanc 1995) firmly site their ‘take’ on the phenomenon of transnationalism – which they have largely been responsible for conceptualising – within the context of the rise of global capitalism, arguing that the combination of advancements of the technological age and more intense patterns of international migration are creating ways of situating the migration experience differently from those of earlier migrants. This ‘positive spin’ in the literature on the transnational migration paradigm emphasises the agency of transnational migrants as actors exploiting the resources available to them to make informed choices about the ways in which they carry out their lives across the territories of two or more nation states. Such a focus, however, arguably risks restricting the transnational space to those labour or economic migrants who are seen to be making empowered decisions and capitalising on the opportunities afforded by globalisation. That kind of transnational lens implies a neglect of any transnational spaces occupied by those who may not have migrated voluntarily, may be subject to stringent immigration control and may have a less than positive (at least initially) transnational experience.

Challenges and other approaches
The main challenges of the transnationalism paradigm are set around arguments that the transnational lens poses nothing new (Foner 1997; Waldinger & Fitzgerald 2004); that it is conceptually woolly (Portes, Guarnizo & Landolt 1999); or, that it depends on methodological nationalism (refuted in Wimmer & Glick Schiller 2003; Gielis 2009). Even those who adopt it as a conceptual framework are sceptical of its applicability to those migrants who cannot be considered to have made their migratory choices purely for economic reasons. But that will usually depend on how the paradigm is interpreted and applied.

Ewa Morawska (2001), one of the ‘transnationalism-as-a-new-paradigm-skeptics’, maintains that earlier practices of diaspora differed not at all from today’s transnationals: ‘Lifeworlds and diaspora politics of turn-of-the-century immigrants share many of the supposedly novel features of present-day transnationalism’ (2001, 178). Roger Waldinger and David Fitzgerald (2004) in their questioning of transnationalism argue that the nation state and political control and constraint in the forming of communities means that what migration scholars describe as transnationalism is ‘usually its opposite’ (Waldinger & Fitzgerald 2004, 1178). Countered by Glick Schiller and Peggy Levitt (2006), for Waldinger and Fitzgerald transnationalism is dependent on freedom of movement. They maintain that the conditions under which transnational ties are able to flourish and develop are not usually permitted under the control of the sovereign nation state which sees as its ultimate goal the preservation of the identity and culture of the majority. Waldinger and Fitzgerald, then, seem to imply that any transnationalism which does not adhere to the somewhat restrictive criteria as stipulated by Portes and his colleagues (that is to say, any transnational ties which could be considered to be transnational being and belonging over transnational acting) is a rather watered down ‘continuum’ version of the ‘truer’ transnationalism. Waldinger and Fitzgerald refer to non-continuous cross-border activity as ‘something more erratic and less intense’. This also has resonances with the ways in which others have sought to differentiate between the varying intensities of transnational affiliations as expressed by those who migrate. Luis Eduardo Guarnizo (2000) for instance, detailed in Levitt (2001), refers to ‘expanded’ transnationalism in contrasting occasional sporadic migrant responses to political crises or national disasters in the homeland with the ‘core transnationalism’ of habitual, regular, patterned and predictable activity. Similarly, José Itzigsohn and Silvia Giorguli Saucedo (2002) make reference to ‘narrow’ and ‘broad’ transnationalism in making the distinction between continuous and occasional transnational practices. Faist, Fauser and Reisenauer (2013) however reject what they see as a binary distinction between the different intensities of behaviour and instead argue for transnationality being viewed on a continuum of low to high.

Transnationalism, diaspora and nationalism
Given the ‘national’ element of transnationalism, it is surprising how little of the literature draws upon the main theories of nationalism. These debates are not foregrounded to the same extent as they are in the field of diaspora studies which pays considerably more attention to the historic movement of peoples, the factors which contributed to the displacement of entire population groups (inter alia Brah 1996; Cohen 1997; Van Hear 1998) and the relationship between diaspora and ethnie(Smith 2010). One way however in which the transnationalism literature does dovetail with some of the debates on nationalism is in discussing the role of the nation state and assumptions about its role as a primary unit of analysis. One of the reasons why some of the debates present in the nationalism literature have not cross-fertilised into the transnationalism scholarship may have been as a result of a deliberate choice on the part of those scholars who have been responsible for developing the transnational paradigm. Debates especially about whether methodological nationalism is inherent within the transnational lens began early on in the development of the literature (Waldinger & Fitzgerald 2004) and have continued more recently with the publication of Waldinger’s The cross-border connection (2015) and especially within the symposium dedicated to its critique and subsequent ‘defence’ of the transnational optic (see Eckstein; Faist; Glick Schiller; Itzigsohn; Kivisto; Levitt; Waldinger in Ethnic and racial studies 38/13 2015).

Whether transnational activity is viewed as binary or on a continuum focuses on transnationalism as a practice or behaviour essentially quantifiable and measurable in nature. With such a focus on transnational activity, the voices of those who may not remit, vote, own property in the country of origin, have a bank account or even undertake regular visits to the ‘homeland’ but may still retain a deep and complex emotional relationship with the country of origin risk going unheard. Research on transnationalism of forced migrants can give a different slant on the theoretical field (Al-Ali 2002b; Jansen 2008; Van Hear 2014). Much of the debate around the ‘innovation’ of the transnational paradigm seems to have been carried out extraneously to any empirical findings, despite the call by some transnational theorists to ‘ground’ research into the practices of migration – whether transnational or not. Katharyne Mitchell also warns against ‘theorising transnationalism in the abstract’ (Mitchell 1997, 111) arguing that ‘by bringing in “real” bodies, the actual physical, geographical constraints encountered by refugees as they seek to move across space challenges aspatial and abstracted concepts and “serves as a materialist connective to the unimpeded ‘travelling cultures’ and diasporic populations heralded by some theorists”’ (ibid). ‘Bringing in real bodies’ may mean that general conceptualisations are more difficult to land on, which may explain why some theorists prefer to work without them. However, reluctance (whether perceived or actual) to ground theories in the lived experience of migrants then risks conceptual murkiness and exposes the paradigm to prolonged and sometimes territorial debates.

Described by Faist (2010, 9) as ‘awkward dance partners’, the concepts of transnationalism and diaspora run parallel in some of the literature, merging and colliding especially within the context of discussions around community spaces and migrant identities (Bruneau 2010). Treated almost as synonyms by some migration scholars who may interpret each term more expansively, diaspora ‘purists’ are clear in their demarcation of the associations between each term. Khachig Tölölyan (2010, 37) for example, in reference to the Armenian diaspora or ‘transnation’ states: ‘If nations have nationalism, then this transnation has “transnationalism”, a term that in most venues is forbidden to me because, of course, transnationalism already has a more established meaning that developed in the 1970s, as in transnational corporation or transnational terrorism.’ Such associations echo an earlier statement by Jana Evans Braziel and Anita Mannur (2003, 8): ‘While diaspora may be regarded as concomitant with transnationalism, or even in some case consequent of transnationalist forces, it may not be reduced to such macroeconomic and technological flows. It remains, above all, a human phenomenon – lived and experienced.’ Such ‘dehumanisation’ of the transnationalism phenomenon is not present in the arguments of those who emphasise the bottom-up aspect of the transnational lens (Guarnizo & Smith 1998) nor in the focus of those who stress the relationship between transnationalism and communities (Riccio 2001; Sana 2005). Others however also refute the national in transnational, highlighting how the community frame of reference takes precedence over the nation state in the formation of translocal connections and identities.

Such ambivalence towards the concept of transnationalism has certainly been reflected in the literature for its apparent disconnect with the realities of the local (Harney & Baldassar 2007). The ‘nation-state’ focus of the transnational debates has been challenged within the context of the Bosnian diaspora, for example by Hariz Halilovich (2011b) who, in emphasising the importance of zavičaj to the structuring of identity for Bosnians, argues for a ‘trans-local’ as opposed to a ‘trans-national’ conceptualisation. Zavičaj in this sense could be interpreted as loyalty and affiliation to the local ‘neighbourhood’ or more immediate local area rather than the ‘homeland’ as a nation state. Borrowing on the conceptualisations of Arjun Appadurai (1996) and Guarnizo and Michael Peter Smith (1998) and their ‘trans-local’ approach, Halilovich builds on the work of Nadje Al-Ali and Khalid Koser (2002) which discusses the difficulties of the ‘nation’ element of the ‘transnational’ label in applying to Bosnian (and other) refugees. Halilovich argues that the concept of transnationalism is ‘less useful for exploring the relationship between place, movement, identity and memory in forcefully displaced communities from BiH’ (Halilovich 2011b, 168). Those who have been forced from their homes as a result of the nationalist policies of ruling elites may demonstrate a noticeable rejection of affiliation with their sending ‘nation state’ and could instead draw upon more local or regional connections and loyalties in their collectivisation of memory and belonging, which in the Bosnian context could be interpreted as an instrument of defiance against the genocidal practice of ‘ethnic cleansing’ (Halilovich 2011a, 64 and 2013, 231) but could, of course, be equally applicable to the experience of forced migrants from other states.

The relationship between transnationalism/transnationality and assimilation (Guarnizo, Haller & Portes 2003; Sana 2005) and integration is also a focus in the literature (Mazzucato 2008; Gropas, Triandafyllidou, & Bartolini 2014; Schunck 2014). Drawing on Portes’ theory of segmented assimilation and focusing on the infrequent and weak ties identified by others (Levitt), Paolo Boccagni (2012, 117) questions the applicability of the transnational lens and asks:

What is left of its theoretical import […] after establishing that proper transnational activities, aside from remittances, are relatively infrequent; and that such practices are not incompatible with – and are even facilitated by – successful integration overseas?

Such a focus on purported ‘proper’ transnational activities represents a narrower approach to the transnationalism paradigm and suggests that the goal of every migrant is ‘successful integration’ however that may be defined. A focus on integration as an apparent ‘end goal’ and a preoccupation with ‘proper’ transnational activities could risk missing the nuances that are potentially captured with a less restrictive take on the concept.