“…Scholars of the Arab Spring, for example, have observed that countries in which security forces had ethnic or tribal ties to dictatorships, such those in Syria or Libya, were more likely to repress on behalf of the regime (McLauchlin, 2010;Morency-Laflamme & McLauchlin, 2020;Lutterbeck, 2013;Makara, 2013;Bou Nassif, 2015;Johnson & Thurber, 2020; for a review see Brooks, 2017). Stacking tactics, such as recruiting senior officers or parallel military institutions on the basis of shared political identity, have been shown to be effective in limiting the success of coups (Koren, 2014;Roessler, 2016;De Bruin, 2018), in fueling them (Harkness, 2018), in forestalling democratization (Bratton & Van de Walle, 1997;Harkness, 2017;Hassan, 2017;Allen, 2019) and in catalyzing civil wars (Roessler, 2016). Stacking is thought to impair military success in external and internal conflicts, by undermining efforts to mobilize human capital or to organize militaries to maximize their effectiveness in armed conflict (Brooks, 1998;Lyall, 2020;Pilster & Böhmelt, 2011).…”