4 MOSS ET AL . discussing politics even within the intimacy of their homes, as one person’s crossing of the ‘red lines’ can endanger their families and implicate their entire social network in traitorous, illegal behaviours (Cohen & Arato, 1994, p. 49; Pearlman, 2016; Wedeen, 1999). By suppressing ‘horizontal voice’, regimes suppress the social relations that nourish trust, alternative ideas, identities, and collective resistance (O’Donnell, 1986, p. 7). Because transnational repression extends ‘the scale of domestic political controls into transnational spaces’ (Lewis, 2015, p. 141), the more repressive a regime acts towards their population at home (or against a particular political or ethnic group), the more likely state officials will be to deploy proxy punishment. Changes in the use of proxy punishment are also likely to correlate with fluctuations in regime strength. For instance, as Turkey became increasingly authoritarian under its president, Recep Tayyip Erdoğan, the government increased its reliance on proxy punishment as a means to repress exiles (Popp & Sandberg, 2019). ‘Softer’ authoritarian regimes may be less inclined to use this method when their power and longevity rests on ‘pillars of stability’ other than force and personalistic rule (Gerschewski, 2013; Levitsky & Way, 2010). We therefore expect proxy punishment to be more commonly wielded by highly repressive regimes than semi-authoritarian states or weak democracies.2 That said, proxy punishment can take the form of covert intimidations, such as calls by anonymous regime agents that threaten diasporas’ relatives at home (Amnesty International, 2020). Accordingly, any illiberal government hoping to cultivate legitimacy, investment, and donor support may use proxy punishment to silence international criticism and bolster their image (Dukalskis, 2021). A diaspora community’s host-country will also shape their vulnerability to proxy punishment in direct and indirect ways. While not a prerequisite for diaspora activism, residing in a democracy endows emigrants with a significant degree of political freedoms, access to independent media and advocacy organizations, and political support to leverage against dictatorships. Paradoxically, however, the freer and safer diaspora activists are abroad, the more likely they may be to mobilize against regimes, and the more likely regimes may be to subsequently use proxy punishment against diasporas and their families. Host-country governments cannot prevent acts of repression inside a regime’s sovereign territory, although some governments and international institutions have condemned proxy punishment. In 2019, the European Parliament denounced China’s harassment of Uyghurs abroad, for instance, which forces ‘them to act as informants against other Uyghurs, return to Xinjiang or remain silent about the situation there, sometimes by detaining their family members’ (Amnesty International, 2020). However, such resolutions often lack mechanisms for enforcement and accountability. As a result, reports suggest that diasporas in democracies remain highly vulnerable to proxy punishment, and that instances of threats against families remain underreported (Phipps, 2020; Schenkkan & Linzer, 2021). Given the far-reaching consequences of proxy punishment for diaspora communities and their families in the homecountry, understanding this form of transnational repression is a pressing topic. Despite the growing acknowledgement of this practice, however, we lack systematic research on its forms and the effects it has on transnational activism. Our study addresses this gap using original evidence from four Middle Eastern diasporas. Doing so advances theories of transnational activism and repression by demonstrating the types and consequences of high-risk mobilization for diasporas who—by virtual of their cross-border network ties—remain embedded in two worlds at once, and face collective risks and costs for speaking out (Levitt & Glick Schiller, 2004). DATA AND METHODS This paper draws on data collected for separate but related research projects. Evidence from the first author comes from a comparative study undertaken between 2011 and 2014 to investigate when and how Libyan and Syrian diaspora members mobilized to support the 2011 Arab Spring uprisings from the United States and Great Britain. The second author gathered original data on the methods, mechanisms, and effects of transnational repression against exiled activists from Iran, Syria, and Egypt. This project involved more than 60 interviews conducted in 2015, 2018, and 2019, with respondents residing in 12 host-countries across Europe, North America, Turkey, and Tunisia. Evidence from the third author comes from interviews on activism and repression among Egyptian exiles conducted in 2018 and 2019