Post‐Truth Politics, Digital Media, and the Politicization of the Global Compact for Migration

The debate over the Global Compact for Safe, Orderly and Regular Migration (GCM) in late 2018 showcases the crucial role of digital and, in particular, social media as vehicles of disinformation that populist actors can exploit in an effort to create resentment and fear in the public sphere. While mainstream political actors and legacy media initially did not address the issue, right‐wing populist actors claimed ownership by framing (presumably obligatory) mass immigration as a matter of social, cultural, economic, and not least political risk, and created an image of political and cultural elites conspiring to keep the issue out of the public sphere. Initially advanced via digital and social media, such frames resonated sufficiently strongly in civil society to politicize the GCM in various national public spheres. In this article, these dynamics are explored by comparing the politicization of the GCM in three EU member states, namely Germany, Austria, and Sweden. Using a process‐tracing design, the article (a) identifies the key actors in the process, (b) analyzes how the issue emerged in social and other digital media and travelled from digital media into mainstreammass media discourse, and finally (c) draws com‐ parative conclusions from the three analyzed cases. Particular emphasis is placed on the frames used by right‐wing populist actors, how these frames resonated in the wider public sphere and thereby generated communicative power against the GCM, ultimately forcing the issue onto the agenda of national public spheres and political institutions.


Introduction
The debate over the Global Compact for Safe, Orderly and Regular Migration (GCM) in late 2018 showcases the crucial role of social and other digital media as vehicles of disinformation that populist actors can exploit in order to politicize issues by creating resentment and fear in the public sphere. Adopted at an intergovernmental conference in Marrakesh in December 2018, the GCM provides an assessment of the political issues brought about by international migration and formulates legally non-binding recommendations for dealing with them (cf. Newland, 2019;Pécoud, 2020). While most of the 23 objectives can be categorized as either uncontroversial (e.g., improving migration data) or merely aspi-rational (e.g., reducing negative drivers of migration), others were ultimately construed as much more controversial, in particular the aspect of improving opportunities for legal migration (see Newland, 2019, for a more detailed overview). Although the GCM initially did not attract much attention in EU public spheres, a number of EU member states soon began to withdraw their approval of the compact. The aim of this article is to analyze what caused this change of position and, in particular, what role mobilization and politicization processes facilitated by social media infrastructures played in these processes.
Theoretically, the case of the GCM is relevant from a number of perspectives. Against the backdrop of the theme of this thematic issue, the case draws attention to the ways in which the far right mobilized opposition against the GCM through the use of specific frames (see also Godwin & Trischler, 2021) and resentful affect (see also Salmela & Capelos, 2021), ultimately forcing the issue onto the agenda of the wider public sphere and the political system. Against the backdrop of discussions on post-truth politics, the case furthermore highlights (a) the role that inadvertent misinformation as well as deliberate disinformation can play in mobilization processes in the public sphere, and (b) what impact this may have on institutional decision making. In addition, the case also offers methodologically relevant insights into the operationalization of how communicative power is generated in the public sphere: Drawing on earlier work, communicative power generation is seen to be initiated through framing processes and depends on the extent to which frames advanced, e.g., via social media resonate in the public sphere at large (Conrad & Oleart, 2020). Finally, the case highlights that such mis-/disinformation and mobilization processes would be inconceivable in the absence of social and other digital media infrastructures.
The empirical analysis highlights the causal pathways through which opposition against the GCM moved from the fringes of the political spectrum via social/digital media into the wider public sphere and ultimately into the institutions of the political system. This process is analyzed through a comparative case study with a process-tracing design (Beach & Brun Pedersen, 2013). The study analyzes three cases of countries where the debate on the GCM, though ultimately short-lived, was particularly contentious: Germany, Austria, and Sweden. These are illustrative cases, chosen primarily for the purpose of demonstrating how far-right actors have used social and other digital media to cause outrage about the GCM, what impact this has had on broader public debate and what responses it ultimately elicited from institutional actors within the political system.
Following this short introduction, the next section presents the article's theoretical argument on post-truth politics, digital media and right-wing mobilization against the GCM. Section 3 presents the analytical framework, while Section 4 presents the empirical analysis. The article ends with a concluding discussion in Section 5.

Post-Truth Politics, Digital Media, and Right-Wing Mobilization Against the GCM
The short-lived politicization of the GCM is not merely a textbook example of the impact of social media in contexts characterized by politicization, polarization and disinformation (cf. Tucker et al., 2018). The causal impact of mis-/disinformation about the GCM also makes it an illustrative case for the broader phenomenon of post-truth politics.
Despite the growing popularity of the concept (e.g., Farkas & Schou, 2020;MacMullen, 2020;McIntyre, 2018;Newman, 2019), theoretical debates on post-truth pol-itics clearly underline how difficult the concept is to define, both in terms of its originality/novelty and the severity of the challenge that it presents to liberal democracies. In the Oxford English Dictionary, where post-truth was chosen as the word of the year in 2016, the concept was defined as "relating to or denoting circumstances in which objective facts are less influential in shaping public opinion than appeals to emotion and personal belief" (Post-truth, n.d.). This definition rhymes well with the communicative processes surrounding the adoption of the GCM. The theoretical point of departure in this article connects post-truth politics to a profound transformation in political culture, characterized by a loss of the "symbolic authority of truth" in the public sphere (Newman, 2019). According to this view, the extent to which factually correct information matters in political debate appears to be fading. In fact, post-truth politics is characterized by the idea that facts themselves are becoming contentious, thereby undermining the distinction between facts and opinions that Hannah Arendt saw as an indispensable precondition for political dispute: There cannot be any meaningful discussion on political issues in the absence of a commonly accepted factual basis (Newman, 2019). Furthermore, post-truth politics is characterized by an undermining of what Habermasin his Theory of Communicative Action-still held to be something that could be taken for granted, namely the "implicit validity claims" raised in interpersonal communication (Habermas, 1981): The idea that we can trust that the person we are talking to actually means what they say and believe it to be true, at least to the best of their knowledge.
Beyond this speaker dimension, MacMullen (2020) has furthermore drawn attention to what we may call the audience dimension of post-truth politics: Post-truth politics is also characterized by audiences who are seemingly indifferent about the factual veracity of the information they are exposed to. People with this kind of "motivationally postfactual" attitudes could know with ease whether or not information given to them is correct but accept the information regardless because it confirms their previously held beliefs, gives them a good feeling and/or a sense of community (MacMullen, 2020). Given the extent to which the politicization of the GCM was premised on disinformation (as the analysis will demonstrate), this is an important point of departure.
In this context, social media are viewed by most scholars to play an important role (Bennett & Pfetsch, 2018;Farkas & Schou, 2020;McIntyre, 2018;Sunstein, 2017), all the more so as it has been demonstrated that false news stories travel much faster online than true ones (Vosoughi et al., 2018). The analysis presented in this article addresses this connection between social (and other digital) media and post-truth politics: Social media are not simply used in an effort to mobilize against and politicize a particular issue, but rather provide an infrastructure that allows for the inadvertent spread of misinformation as well as for the deliberate spread of disinformation about the issue at stake. In this context, it has to be pointed out that although mis-/disinformation are at times used interchangeably, misinformation may be unintentional, whereas disinformation essentially refers to "misinformation that is deliberately propagated" (Guess & Lyons, 2020, p. 11; see also Tucker et al., 2018). Theoretical arguments about post-truth politics, in combination with observations about the role of social and other digital media in such contexts, clearly call for more empirical research on processes in which mis-/disinformation has had politically relevant outcomes. Debates on the GCM are well-suited for this kind of analysis: Although they were ultimately relatively short-lived and arguably had limited immediate political impact beyond the sudden politicization of the GCM, they were indicative of the kind of polarization and "disrupted public spheres" (Bennett & Pfetsch, 2018) that have increasingly come to characterize liberal democracies in the wake of the rise of digital and social media (Barberá, 2020;Persily & Tucker, 2020;Sunstein, 2017).

Methodological Aspects
The article proposes a causal mechanism that explains the short-lived politicization of the GCM between the time of the agreement on the draft text in July 2018 and the adoption of the GCM in December 2018. During this period, a number of states (including one which is analyzed here, namely Austria) withdrew from the compact, which raises questions about the reasons why some countries changed course on a matter that they had just agreed on. The causal mechanism consists of four parts, which can be summarized as (a) initial news reporting; (b) silence in the public sphere and mobilization in the digital sphere; (c) contestation by institutional actors; and (d) contestation of and support for the GCM in mainstream media (see Figure 1). First, news on the agreement on the draft text of the GCM in July 2018 was reported in legacy media in the analyzed countries. Legacy media are here taken to include traditional mass media such as daily newspapers and/or public broadcasters, but also their respective online versions (cf. Davis, 2019). At this point, the GCM was framed predominantly as a problem-solving instrument and was neither made the object of opinion-making journalism nor sparked any immediate debate in other (visible) forums of the public sphere. Second, civil-society actors at the domestic level-both organized and unorganized-started mobilizing against the compact, triggered either by news reporting on the GCM draft text or by events such as the announcement of Hungary's withdrawal from the compact. This mobilization took place to a large extent (though not exclusively) via social and other digital media. As the analysis will show, blogs played an important role in this process, although their resonance clearly depended on amplification achieved through sharing via social media. Increasingly, the GCM was then also framed as a matter of risk. Third, mobilization against the GCM on social media began to resonate in the broader public sphere, in particular as representatives of political parties began to address and criticize aspects that had previously seemed uncontroversial. The line between these two parts of the causal mechanism may be somewhat blurry, since some right-wing populist politicians also used social media to participate in the initial mobilization against the GCM. The third part of the causal mechanism is however characterized by the increasing contestation of the GCM also by other and more moderate institutional actors. At this stage, these actors found themselves compelled to respond to the apparently intensifying public opposition to the compact, not least with regard to claims that parliaments and/or the general public had been kept in the dark about an issue construed as highly sensitive. This led to the fourth step of the causal mechanism: As institutional actors began to address presumably controversial aspects of the GCM, the issue was increasingly also taken up by legacy media, which in turn had an impact on the way the GCM was framed; while some legacy media reported on disinformation campaigns and attempted to clarify the actual

Predominance of opportunity frames
Step 1: IniƟal News reporƟng Mainstram media report about agreement on GCM

Emergence of risk and silence frames
Step 2: Silence in Legacy Media and MobilizaƟon in the Digital Sphere

Right-wing actors mobilize against the GCM on digital media
AdopƟon of risk and silence frames in the wider public sphere Step 3: ContestaƟon by InsƟtuƟonal Actors InƟtuƟonal actors begin to poliƟcize the GCM AdopƟon of risk and silence frames in some conservaƟve media Step

4: ContestaƟon of and Support for the GCM in Mainstream Media
Mainstram media parƟcipate in the debate on the GCM form, content and ambitions of the compact, others adopted the frames advanced via social media and either criticized the previous lack of debate on the GCM or presented the compact as a matter of risk and/or threat.
The dynamics of the politicization of the GCM vary across the analyzed states, but the analysis reveals that a broader causal mechanism was at play across countries.
In an effort to refine the causal mechanism in light of empirical findings from the three countries, the analysis (a) develops a timeline of the politicization of the GCM; (b) identifies the most relevant actors in this process; (c) analyzes the frames used by these actors in making sense of the GCM and its consequences, in particular as regards differences in the frames used by actors on digital/social as opposed to legacy media; and (d) discusses the importance of social media infrastructures as a prerequisite for politicizing the GCM and thereby forcing it (back) onto the agenda of the political system.
The analysis is based both on legacy media material (both quality and tabloid newspapers) and social and digital media material. The content analysis of legacy media material is based on a total of 322 articles published between July and December 2018. All articles were collected via the websites of the respective newspapers (see Table 1 for an overview). The German sample consists of articles from the conservative daily Die Welt, the liberal daily Süddeutsche Zeitung, the left-alternative daily die tageszeitung, the daily tabloid Bild, and the liberal weekly Die Zeit. The Austrian sample consists of articles from the left-liberal daily Der Standard, the liberal daily Die Presse, the conservative weekly Wochenblick, and the daily tabloid Kronen-Zeitung. The Swedish sample consists of articles from the liberal daily Dagens Nyheter, the conservative daily Svenska Dagbladet, the liberal tabloid Expressen, and the social democratic tabloid Aftonbladet. In order to trace the development of the respective publications' coverage of the GCM, the publication date and the type of article were coded for all 322 articles. This was done in order to ascertain when the debate started in the analyzed countries, what triggered it and whether the debate on social media preceded or merely accompanied the debate in mainstream media and the wider public sphere. But the types of articles published also reflect the increasing politicization of the issue: While early coverage of the GCM took place predominantly in the form of news reporting, the frequency of opinion articles increased as the debate intensified. Especially towards the end of the analyzed period, the sampled newspapers published an increasing number of editorials, signed commentaries and op-ed articles. However, the newspaper sample also included a considerable share of analytical background articles that were neither purely news nor opinion articles. In order to simplify the analysis, articles were coded as belonging to one of three categories, i.e., (a) news, (b) background and/or analysis, or (c) opinion articles. Opinion articles included editorials, signed commentaries, op-eds and also interviews, in which invited speakers are given the opportunity to express and explain their views about an issue at hand.
For the frame analysis, on the other hand, a sample of 60 articles (20 per country) was selected. For each country, five articles were sampled for the month of July, ten for October and November, and five for December. Priority was given to the articles that most adequately reflected the diversity of views in the broader debate on the GCM, that is: Whenever possible, articles that are supportive as well as articles that are critical of the GCM (or aspects thereof) were selected. Preference was furthermore given to opinion pieces. This was done in an effort to capture the increasing contentiousness of the debate on the GCM, which is seen as an indicator of the compact's increasing politicization. Nevertheless, the sample also reflects the predominance of news reporting and analytical articles, in particular in the month of July.
In the frame analysis, frames were identified inductively and refined in successive rounds of coding. The frame analysis includes all diagnostic and prognostic frames, i.e., frames that either identify and define problems connected to the GCM or propose solutions to these perceived problems, respectively (cf. Benford & Snow, 2000;Snow & Benford, 1988). In particular, the frame analysis considers the impact of what is referred to, in this thematic issue, as "resentful affect" (cf. Capelos & Demertzis, 2018;Capelos & Katsanidou, 2018), arguing that the politicization of the GCM was premised on the deliberate use of a highly specific set of frames. In this regard, emphasis is placed on the aspect of timing, i.e., the question to what extent the initial silence in the public sphere gave right-wing actors an opportunity to set the tone in the debate through the use of resentful affect and disinformation on social media. Most of the frames identified in the analysis belong to the categories of risk, opportunity or process frames, i.e., frames that construed the GCM as a matter of risk (see also Godwin & Trischler, 2021) as an opportunity, or that addressed issues concerning the process of drafting and negotiating the compact. A full list of all identified frames is available in Supplementary File 1.
The social media analysis, on the other hand, is based on material collected on Twitter between 1 July and 31 December 2018. To begin with, the analysis identified (a) the most important hashtags around which the debate crystallized and (b) the most impactful users in the sampled period. The most important hashtags were identified by performing a keyword search based on the most commonly used Swedish and German words for the GCM (i.e., "migrationsavtal" and "Migrationspakt," respectively). Combining this keyword search with predefined minimum levels of engagement (i.e., "likes" and "retweets") made it possible to identify the most salient hashtags in the analyzed period. In a second step, these keywords and hashtags were then used to identify the most impactful users. Impact was also defined in terms of engagement: The most impactful users were considered to be those whose tweets generated the highest numbers of likes and retweets. This dual sampling strategy made it possible to focus the social media analysis both on the role of impactful individuals and at the same time also to analyze other content published under the same hashtags. Since a number of tweets also included links to other content by these individuals (notably blogs), these were also included in the analysis.

The Unexpected Politicization of the GCM in Austria, Germany, and Sweden
The story of the GCM can be read as the story of an unexpected politicization. Politicization is usually understood as a process of "making previously unpolitical matters political," or "moving something into the realm of public choice" (Zürn, 2019, pp. 977-978). This understanding certainly applies in the context of the GCM. After all, all 192 UN member states apart from the United States agreed to the text of the compact on 14 July 2018. Numerous observers have furthermore pointed out that the compact is not a legally binding international treaty (e.g., Guild et al., 2019;Newland, 2019), but merely identifies non-binding policy recommendations as to how governments should address international migration (Pécoud, 2020). Presumably, this is also why the GCM did not attract more attention in the public sphere sooner. Nevertheless, Hungary announced its withdrawal from the compact already four days after the agreement on the draft text, thereby kick-starting the unexpected and short-lived politicization of the GCM, in the wake of which Austria (31 October), Bulgaria (12 November), the Czech Republic (14 November), and Poland (20 November) also withdrew from the compact.
Austria's opt-out from the GCM is perhaps not surprising, given that the country has a right-wing populist party in government. Still, the decision to change course just three and a half months after agreeing to the draft text constitutes a puzzle, in particular as Austria had held the Council Presidency of the European Union at the time. Sweden and Germany, by contrast, merely have significant right-wing populist parties in parliament, namely the Alternative for Germany (AfD) and the Sweden Democrats (SD), respectively. Both countries witnessed contentious debates on the GCM in October and November, but nonetheless did adopt the compact at the Marrakesh conference. In the German case, the AfD played a key role in mobilizing against the GCM in Germany, whereas in the Swedish case, the SD's role is somewhat more ambiguous: The party was late to address the issue and focused predominantly on its criticism of the Swedish government for not having informed the public and addressed the issue in the Riksdag-an approach that mirrors the one adopted by forces on the right wing of Angela Merkel's Christian Democratic Union (CDU) in Germany. Parliamentary debates on the GCM only took place in Germany and Austria. In Germany, the parliamentary debate preceded the decision in favor of the GCM on November 29, 2018. In the Austrian case, a debate was held on 21 November 2018, three weeks after the government's announcement of the country's withdrawal from the GCM. In Sweden, the GCM was merely addressed in a hearing in the Riksdag's Foreign Affairs Committee on 29 November 2018.

Initial News Reporting, Silence in Legacy Media, and Mobilization in the Digital Sphere
News about the agreement reached in July 2018 was reported in mainstream media in all three of the analyzed states but neither sparked any debate in the wider public sphere nor was not made the object of opinion-making journalism in legacy media. As illustrated by Figure 2, newspaper coverage of the GCM was in fact fairly slow to pick up. Apart from news coverage of the agreement in July, the months of August and September were characterized by more or less complete silence. As a notable exception, a debate began to intensify in September in the Austrian newspaper Wochenblick (which has a close affinity to the right-wing populist FPÖ). The development of newspaper coverage in Germany mirrors its Austrian counterpart and peaked in November, due to the fact that the Austrian withdrawal on the last day of October also sparked debate in Germany, in particular among the right wing of the CDU. By comparison to the Austrian and German debates, the Swedish debate was even slower to pick up. Here, newspaper coverage did not reach its peak until late November and early December, when the GCM was taken up in the foreign affairs committee of the Riksdag, accompanied by protests in various Swedish cities. Figure 3 shows the distribution of the three main categories of frames used in newspaper coverage of the GCM. In July, the GCM was predominantly framed as an opportunity, most of all by highlighting it as a problem-solving instrument, both in general and as regards strengthening migrants' rights. At this point, risk frames only appeared by reference to statements made by the Hungarian government upon the country's withdrawal from the GCM and were not adopted by the respective publications. These risk frames presented migration in general as a threat and expressed concerns that the GCM may become legally binding with time.
Despite this relative silence on the GCM in the summer, mobilization via social and other digital media notably preceded debate in legacy media in all three states. Germany witnessed a relatively quick start and intensification of the debate on Twitter, where the hashtag #MigrationspaktStoppen emerged as early as in mid-September. Other important hashtags in the mobilization process on Twitter included #Migrationspakt, #StopptDenPakt (Stop the pact) or #Umvolkung (i.e., replacement of native populations with immigrants). These hashtags were frequently used in combination. A number of the AfD's MPs started using the hashtag #MigrationspaktStoppen from early to mid-October, claiming, e.g., that "project resettlement is on!" (Bystron, 2018  (Alternative for Germany, 2018). This phase was also characterized by considerable activity on the part of conservative bloggers (e.g., Roland Tichy, Vera Lengsfeld, David Berger or Sylvia Pantel, an MP and spokesperson of the Berliner Kreis within the CDU), whose contributions were shared (and thereby amplified) via social media. In this mobilization process in Germany, the GCM was predominantly framed as a matter of risk, but process frames-in particular the types of silence frames that were later also adopted in mainstream media coveragewere also commonly used (e.g., Pantel, 2018aPantel, , 2018b. In terms of misleading frames, this initial phase was characterized by ideas of economic, social and/or cultural risk-essentially the idea that, with the GCM, "all hurdles for migration are supposed to fall" (Tichy, 2018; see also Godwin & Trischler, 2021), that the "UN wants to compel states in the West to accept a massive relocation of migrants," and that political elites are fully aware that the GCM would fundamentally transform European societies (Lengsfeld, 2018). On Twitter, such risk frames were expressed in even more drastic terms, suggesting that the consequence of the GCM would be "a fight for resources and civil war" (Landkauf, 2018), that the German population would "flip and become predominantly Islamic and African" within two generations, while democracy would "mutate into Islamic authoritarianism" (ibikus31, 2018).
In Sweden, the mobilization process began somewhat later, instigated by reports about a warning of the Polish government against the GCM (as a threat to national security and migration laws) that were shared on Twitter in October, primarily among rightwing social media users. Initially, this mobilization crystallized around generic hashtags such as #svpol and #migpol. As the debate intensified, however, it increasingly crystallized around the hashtags #Mynttorget and #Mynttorgetprotesterna, named after the square in Stockholm where demonstrations took place from early December onwards. Two bloggers played a key role in this mobilization, namely Katerina Janouch and Jenny Piper. Their contributions were widely shared on social media and were therefore instrumental in framing the GCM on social media. The former ultimately also organized the demonstrations against the GCM in Stockholm. Both risk and process frames were central in this early mobilization against the GCM. Regarding the latter category, silence frames were particularly salient, most notably the idea that critical debate on the GCM was being silenced by the political elite in Sweden, which had allegedly plotted to keep the public in the dark about the compact and adopt it without the general public becoming aware of it (e.g., Piper, 2018). Risk frames, on the other hand, were used to emphasize the compact's alleged lack of distinction between legal and illegal migration, which was taken as tantamount to migrants receiving the right to settle in any country of destination. Consequently, the GCM is construed as implying dramatic negative social, economic and/or cultural consequences. Resentful affect plays an important role here as well, as some speak of an "assault on Sweden" (Janouch, 2018a) and present the GCM as opening the doors to increasing sexual violence (Janouch, 2018b;Zackrisson, 2018).
As the mobilization against the GCM gained traction on social media, mainstream media were still notably silent on the issue, reflecting that the issue was not up for debate in the Swedish parliament. In fact, the Swedish government's apparent silence on the issue resulted in the subsequent prominence of silence frames on social media, which later also resonated in mainstream media. In this initial phase, the SD did not pick up the issue, which an increasing number of Twitter users expressed bewilderment about. This void was however quickly filled by smaller (right-wing) parties and movements, such as the Alternative for Sweden (AfS) and the Populists. The former was quick to claim ownership of the issue by branding itself as "the only Swedish party to have taken a stance against the UN's migration agreement, of course" (Alternative for Sweden, 2018). As discussed below, it was the increasing resonance of silence frames that ultimately forced the other parties to respond, in particular the SD, thus marking the link between the first and second part of the causal mechanism in the process.
In the Austrian case, finally, mobilization on social media began sooner than in Sweden and tended at least in part to coincide with the mobilization process observable in Germany. For one, the shared language resulted in the use of shared hashtags. More importantly, the Identitarian Movement (Identitäre Bewegung), which was instrumental in the Austrian mobilization process, is also active in Germany, and content by the Identitarian Movement's most prominent proponent Martin Sellner was frequently shared by German users. In Austria, the movement's digital media campaign against the GCM began as early as September 2018 and was amplified by the organization of demonstrations in October and November. Some media have pointed out that the movement's reading of the GCM was also highly influential in shaping the position of Vice Chancellor Heinz-Christian Strache (Baumann, 2018). Soon after the start of the Identitarian Movement's campaign, Strache expressed his opposition to the GCM, stating as early as 10 September that he is "absolutely critical and negative" about the GCM, and two weeks later that he would not support any UN compact in which migration issues are not decided on by Austria ("UN-Migrationspakt: Türkis-Blau mahnt zu Vorsicht," 2018). The Identitarian Movement's reading of the GCM was also adopted by other media: first by the newspaper Wochenblick (which has a close affinity to Strache's FPÖ), later by the FPÖ blog unzensuriert, and finally by the tabloid newspaper Kronenzeitung. Given Strache's statement that signing the compact would have been a violation of the coalition agreement with the Austrian People's Party (ÖVP), it is highly plausible to attribute the Austrian government's change of position on the GCM to the junior coalition partner FPÖ and, in particular, Vice Chancellor Strache.

Resonance in the Wider Public Sphere: Contestation by Institutional Actors
While the mobilization process on social media marked the starting point of the sudden politicization of the GCM in the German case, the next step in the process begins when contestation of the compact starts to surface also among representatives of political parties and/or MPs. These now find themselves more or less forced to position themselves in relation to increasing concerns about the GCM.
In Sweden, this refers primarily to the SD, who had initially not addressed the GCM. But in addition, the Moderates also began to question the apparent silence that had surrounded the drafting and negotiation of the GCM. In particular, the party criticized the lack of an analysis of the consequences of the compact, which was also expressed in a subsequent hearing in the Swedish parliament's foreign affairs committee on 29 November and became a central theme in the ensuing debate in the wider public sphere. As Figure 2 shows, this also coincided with a significant increase in mainstream media coverage, which only reached its peak in Sweden in late November and early December. This increasing contestation over the GCM's content and the process pursued by the Swedish government is also reflected in the frames used in mainstream media coverage of an increasingly contentious debate. Figure 3 illustrates that whereas opportunity frames dominated the (albeit limited) news coverage in July, it was indeed risk frames that dominated in October and November. In part, this reflects a shifting emphasis among institutional actors: At this point, even more moderate actors began to adopt the types of process frames initially advocated by far-right actors via social media, specifically as regards the question why the potential consequences of the GCM had not been explored, why the issue wasn't addressed in the Swedish parliament and why the Swedish government did not do more to "anchor" the GCM in the public sphere by raising awareness of and building support for the compact.
In Germany, criticism of the GCM began to surface in more conservative circles within Angela Merkel's CDU, specifically in the Werte Union and the Berliner Kreis. To some extent, such concerns were expressed also via social media. For instance, the Werte Union started using the prominent hashtag #MigrationspaktStoppen from mid-October (Werte Union Berlin, 2018), urging that the GCM should be discussed both at the CDU's convention in early December and in the Bundestag. Similarly, the MP Alexander Mitsch (also a member of the Werte Union) used his Twitter account to call for parliamentary debate and corrections to the GCM, later claiming credit for the Werte Union for having generated debate on the GCM in the German public sphere. This increas-ing contestation also had a considerable impact both on the amount of coverage of the GCM in Germany in November and on the increasing use of risk and process frames. Questions about a lack of discussion about the compact gained prominence in this phase, underlining the impact of social media mobilization on the frames used by at least a certain segment of institutional actors. Despite the fact that party-political actors have claimed credit for putting the GCM onto the agenda, it is clear that the impetus came from mobilization processes taking place on social media, as underlined by the initial silence in mainstream media and the apparent lack of interest on the part of institutional actors (apart from the AfD).

Resonance in the Wider Public Sphere: Contestation of, and Support for, the GCM in Mainstream Media
This leaves the question of when and to what extent the increasing politicization moved from institutional actors into the arenas of opinion-making journalism. This fourth step of the causal mechanism shows that social media mobilization not only resulted in institutional actors (re-)politicizing the GCM, but also had an impact on the frames employed on the opinion pages of the respective publications.
With the exception of the Wochenblick, resonance of social media frames in Germany and Austria remained somewhat limited in mainstream media, in particular as regards the various risk frames that had been advanced on social media. Instead, the other sampled newspapers focused on reporting, analyzing, and commenting on the extent to which the belated politicization of the GCM was a result of the spread of mis-/disinformation on social media (e.g., Vehlewald, 2018). Consequently, as illustrated by Figure 3, process and opportunity frames played a more important role at this point than risk frames, due also to the fact that many of the sampled publications used the adoption of the GCM on 10 December as an occasion to analyze its opportunities, but also to comment on deficits in the process. In particular, the more progressive publications left no doubt that governments could and should have gone to greater lengths to raise awareness of and build support for the GCM already in the drafting process. The liberal daily Süddeutsche Zeitung concluded that the German government had simply "failed" in this regard and should learn its lesson from this "disaster" (Kastner, 2018), i.e., that the far right had been given an opportunity to spread disinformation about the GCM. In a similar vein, the liberal Der Standard argued that although there had certainly been enough to discuss, there had evidently been no interest in opening a debate on an issue as controversial and potentially divisive as migration (Hoang, 2018).
Notably, however, the end of the process also witnessed a much more ambivalent perspective on the GCM than could be expected from the initial lack of interest. In the end, some of the conservative publications came out in more or less complete opposition to the GCM and presented opinions that highlighted the risk frames advanced in the mobilization process on social media (e.g., Aust & Büchel, 2018;Schmid, 2018). A similar process could also be observed in Sweden, where a number of editorials took issue with the process of dealing with the GCM at the domestic level and proposed, at the very least, to postpone the adoption of the compact (e.g., Dahlman, 2018;Sonesson, 2018).

Conclusions
The analysis has shown that the case of the GCM can be taken as a textbook example for the unexpected politicization of an issue more or less purely because of the ability of right-wing actors to exploit social media as an infrastructure for the spread of mis-/disinformation. In this article, this process was highlighted through the use of a comparative case study that traced the development of the GCM's politicization in three EU member states. Although the process followed its own dynamics in the three chosen countries, a similar causal mechanism was at play in all three cases. All three countries had participated in the negotiations and agreed on the draft text that was finalized in July 2018. Although mainstream media had reported on this achievement, this did not generate any debate within the political institutions or the wider public spheres, but ultimately sparked a mobilization process on social and other digital media. In this mobilization process, the ability of actors on the far right both to frame the issue and to exploit these frames was instrumental in creating a sense of urgency that allowed the issue to reach the agenda of the wider public sphere and the political system. The initial silence in the wider public sphere-which far-right actors ironically framed as a strategic move on the part of the political establishment to keep the public in the dark about the implications of the GCM-was in fact what allowed far-right actors and right-wing populists alike to claim ownership of the issue in the first place. As the mobilization process gained traction on social and digital media, accompanied by increasing protests on the streets, mainstream political actors as well as mainstream media were forced to position themselves on the issue. At this point, however, the frames advanced via social and other digital media had already resonated in the three public spheres.
Given that the empirical basis of this article is limited to such a small number of states, it is evidently difficult to draw any generalizing conclusions. Nonetheless, the article's empirical findings underline that the GCM is a highly relevant case against the backdrop of broader debates on the role of social and other digital media in post-truth politics, and the implications of these findings have to be discussed in that context. Future research will need to address whether similar processes can also be observed in other cases and in a larger number of states, whether in the EU or elsewhere. If similar patterns can be shown on a broader empirical scale, then the mobilization and politicization processes that could be witnessed in the run-up to the adoption of the GCM in December 2018 are certainly highly ambivalent as regards the role of the public sphere in liberal democracy: The process was based on the-presumably strategic-use of mis-/disinformation, and this mis-/disinformation appears to have fallen onto fertile ground in the digital sphere. This provided an opportunity for right-wing populist actors to also claim ownership of the issue by exploiting the frames constructed in the digital sphere even further. From the perspective of deliberative democracy and communicative power generation, the ability of organized civil society to identify concerns and amplify them in the public is traditionally hailed as bearing significant emancipatory potential. But as the case of the sudden and unexpected politicization of the GCM via the digital sphere has indicated, this mechanism can be turned onto its head seemingly easily by skillful political actors, all the more so in a political culture that is increasingly characterized by post-truth politics.